1<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3 4<html> 5 6<head> 7 8<title>Postfix Configuration Parameters </title> 9 10<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 11 12</head> 13 14<body> 15 16<h1><img src="postfix-logo.jpg" width="203" height="98" alt="">Postfix Configuration Parameters </h1> 17 18<hr> 19 20<h2> Postfix main.cf file format </h2> 21 22<p> The Postfix main.cf configuration file specifies a very small 23subset of all the parameters that control the operation of the 24Postfix mail system. Parameters not explicitly specified are left 25at their default values. </p> 26 27<p> The general format of the main.cf file is as follows: </p> 28 29<ul> 30 31<li> <p> Each logical line is in the form "parameter = value". 32Whitespace around the "=" is ignored, as is whitespace at the end 33of a logical line. </p> 34 35<li> <p> Empty lines and whitespace-only lines are ignored, as are 36lines whose first non-whitespace character is a `#'. </p> 37 38<li> <p> A logical line starts with non-whitespace text. A line 39that starts with whitespace continues a logical line. </p> 40 41<li> <p> A parameter value may refer to other parameters. </p> 42 43<ul> 44 45<li> <p> The expressions "$name", "${name}" or "$(name)" are 46recursively replaced by the value of the named parameter. </p> 47 48<li> <p> The expression "${name?value}" expands to "value" when 49"$name" is non-empty. This form is supported with Postfix version 502.2 and later. </p> 51 52<li> <p> The expression "${name:value}" expands to "value" when 53"$name" is empty. This form is supported with Postfix version 2.2 54and later. </p> 55 56<li> <p> Specify "$$" to produce a single "$" character. </p> 57 58</ul> 59 60<li> <p> When the same parameter is defined multiple times, only 61the last instance is remembered. </p> 62 63<li> <p> Otherwise, the order of main.cf parameter definitions does 64not matter. </p> 65 66</ul> 67 68<p> The remainder of this document is a description of all Postfix 69configuration parameters. Default values are shown after the 70parameter name in parentheses, and can be looked up with the 71"<b>postconf -d</b>" command. </p> 72 73<p> Note: this is not an invitation to make changes to Postfix 74configuration parameters. Unnecessary changes are likely to impair 75the operation of the mail system. </p> 76 77<dl> 78<DT><b><a name="2bounce_notice_recipient">2bounce_notice_recipient</a> 79(default: postmaster)</b></DT><DD> 80 81<p> The recipient of undeliverable mail that cannot be returned to 82the sender. This feature is enabled with the <a href="postconf.5.html#notify_classes">notify_classes</a> 83parameter. </p> 84 85 86</DD> 87 88<DT><b><a name="access_map_defer_code">access_map_defer_code</a> 89(default: 450)</b></DT><DD> 90 91<p> 92The numerical Postfix SMTP server response code for 93an <a href="access.5.html">access(5)</a> map "defer" action, including "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" 94or "<a href="postconf.5.html#defer_if_reject">defer_if_reject</a>". Prior to Postfix 2.6, the response 95is hard-coded as "450". 96</p> 97 98<p> 99Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 100</p> 101 102<p> 103This feature is available in Postfix 2.6 and later. 104</p> 105 106 107</DD> 108 109<DT><b><a name="access_map_reject_code">access_map_reject_code</a> 110(default: 554)</b></DT><DD> 111 112<p> 113The numerical Postfix SMTP server response code for 114an <a href="access.5.html">access(5)</a> map "reject" action. 115</p> 116 117<p> 118Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 119</p> 120 121 122</DD> 123 124<DT><b><a name="address_verify_cache_cleanup_interval">address_verify_cache_cleanup_interval</a> 125(default: 12h)</b></DT><DD> 126 127<p> The amount of time between <a href="verify.8.html">verify(8)</a> address verification 128database cleanup runs. This feature requires that the database 129supports the "delete" and "sequence" operators. Specify a zero 130interval to disable database cleanup. </p> 131 132<p> After each database cleanup run, the <a href="verify.8.html">verify(8)</a> daemon logs the 133number of entries that were retained and dropped. A cleanup run is 134logged as "partial" when the daemon terminates early after "<b>postfix 135reload</b>", "<b>postfix stop</b>", or no requests for $<a href="postconf.5.html#max_idle">max_idle</a> 136seconds. </p> 137 138<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 139(weeks). </p> 140 141<p> This feature is available in Postfix 2.7. </p> 142 143 144</DD> 145 146<DT><b><a name="address_verify_default_transport">address_verify_default_transport</a> 147(default: $<a href="postconf.5.html#default_transport">default_transport</a>)</b></DT><DD> 148 149<p> 150Overrides the <a href="postconf.5.html#default_transport">default_transport</a> parameter setting for address 151verification probes. 152</p> 153 154<p> 155This feature is available in Postfix 2.1 and later. 156</p> 157 158 159</DD> 160 161<DT><b><a name="address_verify_local_transport">address_verify_local_transport</a> 162(default: $<a href="postconf.5.html#local_transport">local_transport</a>)</b></DT><DD> 163 164<p> 165Overrides the <a href="postconf.5.html#local_transport">local_transport</a> parameter setting for address 166verification probes. 167</p> 168 169<p> 170This feature is available in Postfix 2.1 and later. 171</p> 172 173 174</DD> 175 176<DT><b><a name="address_verify_map">address_verify_map</a> 177(default: see "postconf -d" output)</b></DT><DD> 178 179<p> 180Lookup table for persistent address verification status 181storage. The table is maintained by the <a href="verify.8.html">verify(8)</a> service, and 182is opened before the process releases privileges. 183</p> 184 185<p> 186The lookup table is persistent by default (Postfix 2.7 and later). 187Specify an empty table name to keep the information in volatile 188memory which is lost after "<b>postfix reload</b>" or "<b>postfix 189stop</b>". This is the default with Postfix version 2.6 and earlier. 190</p> 191 192<p> 193Specify a location in a file system that will not fill up. If the 194database becomes corrupted, the world comes to an end. To recover 195delete (NOT: truncate) the file and do "<b>postfix reload</b>". 196</p> 197 198<p> Postfix daemon processes do not use root privileges when opening 199this file (Postfix 2.5 and later). The file must therefore be 200stored under a Postfix-owned directory such as the <a href="postconf.5.html#data_directory">data_directory</a>. 201As a migration aid, an attempt to open the file under a non-Postfix 202directory is redirected to the Postfix-owned <a href="postconf.5.html#data_directory">data_directory</a>, and a 203warning is logged. </p> 204 205<p> 206Examples: 207</p> 208 209<pre> 210<a href="postconf.5.html#address_verify_map">address_verify_map</a> = hash:/var/db/postfix/verify 211<a href="postconf.5.html#address_verify_map">address_verify_map</a> = btree:/var/db/postfix/verify 212</pre> 213 214<p> 215This feature is available in Postfix 2.1 and later. 216</p> 217 218 219</DD> 220 221<DT><b><a name="address_verify_negative_cache">address_verify_negative_cache</a> 222(default: yes)</b></DT><DD> 223 224<p> 225Enable caching of failed address verification probe results. When 226this feature is enabled, the cache may pollute quickly with garbage. 227When this feature is disabled, Postfix will generate an address 228probe for every lookup. 229</p> 230 231<p> 232This feature is available in Postfix 2.1 and later. 233</p> 234 235 236</DD> 237 238<DT><b><a name="address_verify_negative_expire_time">address_verify_negative_expire_time</a> 239(default: 3d)</b></DT><DD> 240 241<p> 242The time after which a failed probe expires from the address 243verification cache. 244</p> 245 246<p> 247Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 248</p> 249 250<p> 251This feature is available in Postfix 2.1 and later. 252</p> 253 254 255</DD> 256 257<DT><b><a name="address_verify_negative_refresh_time">address_verify_negative_refresh_time</a> 258(default: 3h)</b></DT><DD> 259 260<p> 261The time after which a failed address verification probe needs to 262be refreshed. 263</p> 264 265<p> 266Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 267</p> 268 269<p> 270This feature is available in Postfix 2.1 and later. 271</p> 272 273 274</DD> 275 276<DT><b><a name="address_verify_poll_count">address_verify_poll_count</a> 277(default: normal: 3, overload: 1)</b></DT><DD> 278 279<p> 280How many times to query the <a href="verify.8.html">verify(8)</a> service for the completion 281of an address verification request in progress. 282</p> 283 284<p> By default, the Postfix SMTP server polls the <a href="verify.8.html">verify(8)</a> service 285up to three times under non-overload conditions, and only once when 286under overload. With Postfix version 2.5 and earlier, the SMTP 287server always polls the <a href="verify.8.html">verify(8)</a> service up to three times by 288default. </p> 289 290<p> 291Specify 1 to implement a crude form of greylisting, that is, always 292defer the first delivery request for a new address. 293</p> 294 295<p> 296Examples: 297</p> 298 299<pre> 300# Postfix ≤ 2.6 default 301<a href="postconf.5.html#address_verify_poll_count">address_verify_poll_count</a> = 3 302# Poor man's greylisting 303<a href="postconf.5.html#address_verify_poll_count">address_verify_poll_count</a> = 1 304</pre> 305 306<p> 307This feature is available in Postfix 2.1 and later. 308</p> 309 310 311</DD> 312 313<DT><b><a name="address_verify_poll_delay">address_verify_poll_delay</a> 314(default: 3s)</b></DT><DD> 315 316<p> 317The delay between queries for the completion of an address 318verification request in progress. 319</p> 320 321<p> 322The default polling delay is 3 seconds. 323</p> 324 325<p> 326Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 327</p> 328 329<p> 330This feature is available in Postfix 2.1 and later. 331</p> 332 333 334</DD> 335 336<DT><b><a name="address_verify_positive_expire_time">address_verify_positive_expire_time</a> 337(default: 31d)</b></DT><DD> 338 339<p> 340The time after which a successful probe expires from the address 341verification cache. 342</p> 343 344<p> 345Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 346</p> 347 348<p> 349This feature is available in Postfix 2.1 and later. 350</p> 351 352 353</DD> 354 355<DT><b><a name="address_verify_positive_refresh_time">address_verify_positive_refresh_time</a> 356(default: 7d)</b></DT><DD> 357 358<p> 359The time after which a successful address verification probe needs 360to be refreshed. The address verification status is not updated 361when the probe fails (optimistic caching). 362</p> 363 364<p> 365Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 366</p> 367 368<p> 369This feature is available in Postfix 2.1 and later. 370</p> 371 372 373</DD> 374 375<DT><b><a name="address_verify_relay_transport">address_verify_relay_transport</a> 376(default: $<a href="postconf.5.html#relay_transport">relay_transport</a>)</b></DT><DD> 377 378<p> 379Overrides the <a href="postconf.5.html#relay_transport">relay_transport</a> parameter setting for address 380verification probes. 381</p> 382 383<p> 384This feature is available in Postfix 2.1 and later. 385</p> 386 387 388</DD> 389 390<DT><b><a name="address_verify_relayhost">address_verify_relayhost</a> 391(default: $<a href="postconf.5.html#relayhost">relayhost</a>)</b></DT><DD> 392 393<p> 394Overrides the <a href="postconf.5.html#relayhost">relayhost</a> parameter setting for address verification 395probes. This information can be overruled with the <a href="transport.5.html">transport(5)</a> table. 396</p> 397 398<p> 399This feature is available in Postfix 2.1 and later. 400</p> 401 402 403</DD> 404 405<DT><b><a name="address_verify_sender">address_verify_sender</a> 406(default: $<a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a>)</b></DT><DD> 407 408<p> The sender address to use in address verification probes; prior 409to Postfix 2.5 the default was "postmaster". To 410avoid problems with address probes that are sent in response to 411address probes, the Postfix SMTP server excludes the probe sender 412address from all SMTPD access blocks. </p> 413 414<p> 415Specify an empty value (<a href="postconf.5.html#address_verify_sender">address_verify_sender</a> =) or <> if you want 416to use the null sender address. Beware, some sites reject mail from 417<>, even though RFCs require that such addresses be accepted. 418</p> 419 420<p> 421Examples: 422</p> 423 424<pre> 425<a href="postconf.5.html#address_verify_sender">address_verify_sender</a> = <> 426<a href="postconf.5.html#address_verify_sender">address_verify_sender</a> = postmaster@my.domain 427</pre> 428 429<p> 430This feature is available in Postfix 2.1 and later. 431</p> 432 433 434</DD> 435 436<DT><b><a name="address_verify_sender_dependent_default_transport_maps">address_verify_sender_dependent_default_transport_maps</a> 437(default: $<a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a>)</b></DT><DD> 438 439<p> Overrides the <a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a> parameter 440setting for address verification probes. </p> 441 442<p> This feature is available in Postfix 2.7 and later. </p> 443 444 445</DD> 446 447<DT><b><a name="address_verify_sender_dependent_relayhost_maps">address_verify_sender_dependent_relayhost_maps</a> 448(default: $<a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a>)</b></DT><DD> 449 450<p> 451Overrides the <a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> parameter setting for address 452verification probes. 453</p> 454 455<p> 456This feature is available in Postfix 2.3 and later. 457</p> 458 459 460</DD> 461 462<DT><b><a name="address_verify_service_name">address_verify_service_name</a> 463(default: verify)</b></DT><DD> 464 465<p> 466The name of the <a href="verify.8.html">verify(8)</a> address verification service. This service 467maintains the status of sender and/or recipient address verification 468probes, and generates probes on request by other Postfix processes. 469</p> 470 471 472</DD> 473 474<DT><b><a name="address_verify_transport_maps">address_verify_transport_maps</a> 475(default: $<a href="postconf.5.html#transport_maps">transport_maps</a>)</b></DT><DD> 476 477<p> 478Overrides the <a href="postconf.5.html#transport_maps">transport_maps</a> parameter setting for address verification 479probes. 480</p> 481 482<p> 483This feature is available in Postfix 2.1 and later. 484</p> 485 486 487</DD> 488 489<DT><b><a name="address_verify_virtual_transport">address_verify_virtual_transport</a> 490(default: $<a href="postconf.5.html#virtual_transport">virtual_transport</a>)</b></DT><DD> 491 492<p> 493Overrides the <a href="postconf.5.html#virtual_transport">virtual_transport</a> parameter setting for address 494verification probes. 495</p> 496 497<p> 498This feature is available in Postfix 2.1 and later. 499</p> 500 501 502</DD> 503 504<DT><b><a name="alias_database">alias_database</a> 505(default: see "postconf -d" output)</b></DT><DD> 506 507<p> 508The alias databases for <a href="local.8.html">local(8)</a> delivery that are updated with 509"<b>newaliases</b>" or with "<b>sendmail -bi</b>". 510</p> 511 512<p> 513This is a separate configuration parameter because not all the 514tables specified with $<a href="postconf.5.html#alias_maps">alias_maps</a> have to be local files. 515</p> 516 517<p> 518Examples: 519</p> 520 521<pre> 522<a href="postconf.5.html#alias_database">alias_database</a> = hash:/etc/aliases 523<a href="postconf.5.html#alias_database">alias_database</a> = hash:/etc/mail/aliases 524</pre> 525 526 527</DD> 528 529<DT><b><a name="alias_maps">alias_maps</a> 530(default: see "postconf -d" output)</b></DT><DD> 531 532<p> 533The alias databases that are used for <a href="local.8.html">local(8)</a> delivery. See 534<a href="aliases.5.html">aliases(5)</a> for syntax details. 535</p> 536 537<p> 538The default list is system dependent. On systems with NIS, the 539default is to search the local alias database, then the NIS alias 540database. 541</p> 542 543<p> 544If you change the alias database, run "<b>postalias /etc/aliases</b>" 545(or wherever your system stores the mail alias file), or simply 546run "<b>newaliases</b>" to build the necessary DBM or DB file. 547</p> 548 549<p> 550The <a href="local.8.html">local(8)</a> delivery agent disallows regular expression substitution 551of $1 etc. in <a href="postconf.5.html#alias_maps">alias_maps</a>, because that would open a security hole. 552</p> 553 554<p> 555The <a href="local.8.html">local(8)</a> delivery agent will silently ignore requests to use 556the <a href="proxymap.8.html">proxymap(8)</a> server within <a href="postconf.5.html#alias_maps">alias_maps</a>. Instead it will open the 557table directly. Before Postfix version 2.2, the <a href="local.8.html">local(8)</a> delivery 558agent will terminate with a fatal error. 559</p> 560 561<p> 562Examples: 563</p> 564 565<pre> 566<a href="postconf.5.html#alias_maps">alias_maps</a> = hash:/etc/aliases, nis:mail.aliases 567<a href="postconf.5.html#alias_maps">alias_maps</a> = hash:/etc/aliases 568</pre> 569 570 571</DD> 572 573<DT><b><a name="allow_mail_to_commands">allow_mail_to_commands</a> 574(default: alias, forward)</b></DT><DD> 575 576<p> 577Restrict <a href="local.8.html">local(8)</a> mail delivery to external commands. The default 578is to disallow delivery to "|command" in :include: files (see 579<a href="aliases.5.html">aliases(5)</a> for the text that defines this terminology). 580</p> 581 582<p> 583Specify zero or more of: <b>alias</b>, <b>forward</b> or <b>include</b>, 584in order to allow commands in <a href="aliases.5.html">aliases(5)</a>, .forward files or in 585:include: files, respectively. 586</p> 587 588<p> 589Example: 590</p> 591 592<pre> 593<a href="postconf.5.html#allow_mail_to_commands">allow_mail_to_commands</a> = alias,forward,include 594</pre> 595 596 597</DD> 598 599<DT><b><a name="allow_mail_to_files">allow_mail_to_files</a> 600(default: alias, forward)</b></DT><DD> 601 602<p> 603Restrict <a href="local.8.html">local(8)</a> mail delivery to external files. The default is 604to disallow "/file/name" destinations in :include: files (see 605<a href="aliases.5.html">aliases(5)</a> for the text that defines this terminology). 606</p> 607 608<p> 609Specify zero or more of: <b>alias</b>, <b>forward</b> or <b>include</b>, 610in order to allow "/file/name" destinations in <a href="aliases.5.html">aliases(5)</a>, .forward 611files and in :include: files, respectively. 612</p> 613 614<p> 615Example: 616</p> 617 618<pre> 619<a href="postconf.5.html#allow_mail_to_files">allow_mail_to_files</a> = alias,forward,include 620</pre> 621 622 623</DD> 624 625<DT><b><a name="allow_min_user">allow_min_user</a> 626(default: no)</b></DT><DD> 627 628<p> 629Allow a sender or recipient address to have `-' as the first 630character. By 631default, this is not allowed, to avoid accidents with software that 632passes email addresses via the command line. Such software 633would not be able to distinguish a malicious address from a 634bona fide command-line option. Although this can be prevented by 635inserting a "--" option terminator into the command line, this is 636difficult to enforce consistently and globally. </p> 637 638<p> As of Postfix version 2.5, this feature is implemented by 639<a href="trivial-rewrite.8.html">trivial-rewrite(8)</a>. With earlier versions this feature was implemented 640by <a href="qmgr.8.html">qmgr(8)</a> and was limited to recipient addresses only. </p> 641 642 643</DD> 644 645<DT><b><a name="allow_percent_hack">allow_percent_hack</a> 646(default: yes)</b></DT><DD> 647 648<p> 649Enable the rewriting of the form "user%domain" to "user@domain". 650This is enabled by default. 651</p> 652 653<p> Note: with Postfix version 2.2, message header address rewriting 654happens only when one of the following conditions is true: </p> 655 656<ul> 657 658<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 659 660<li> The message is received from a network client that matches 661$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 662 663<li> The message is received from the network, and the 664<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 665 666</ul> 667 668<p> To get the behavior before Postfix version 2.2, specify 669"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 670 671<p> 672Example: 673</p> 674 675<pre> 676<a href="postconf.5.html#allow_percent_hack">allow_percent_hack</a> = no 677</pre> 678 679 680</DD> 681 682<DT><b><a name="allow_untrusted_routing">allow_untrusted_routing</a> 683(default: no)</b></DT><DD> 684 685<p> 686Forward mail with sender-specified routing (user[@%!]remote[@%!]site) 687from untrusted clients to destinations matching $<a href="postconf.5.html#relay_domains">relay_domains</a>. 688</p> 689 690<p> 691By default, this feature is turned off. This closes a nasty open 692relay loophole where a backup MX host can be tricked into forwarding 693junk mail to a primary MX host which then spams it out to the world. 694</p> 695 696<p> 697This parameter also controls if non-local addresses with sender-specified 698routing can match Postfix access tables. By default, such addresses 699cannot match Postfix access tables, because the address is ambiguous. 700</p> 701 702 703</DD> 704 705<DT><b><a name="alternate_config_directories">alternate_config_directories</a> 706(default: empty)</b></DT><DD> 707 708<p> 709A list of non-default Postfix configuration directories that may 710be specified with "-c <a href="postconf.5.html#config_directory">config_directory</a>" on the command line, or 711via the MAIL_CONFIG environment parameter. 712</p> 713 714<p> 715This list must be specified in the default Postfix configuration 716directory, and is used by set-gid Postfix commands such as <a href="postqueue.1.html">postqueue(1)</a> 717and <a href="postdrop.1.html">postdrop(1)</a>. 718</p> 719 720 721</DD> 722 723<DT><b><a name="always_add_missing_headers">always_add_missing_headers</a> 724(default: no)</b></DT><DD> 725 726<p> Always add (Resent-) From:, To:, Date: or Message-ID: headers 727when not present. Postfix 2.6 and later add these headers only 728when clients match the <a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> parameter 729setting. Earlier Postfix versions always add these headers; this 730may break DKIM signatures that cover non-existent headers. </p> 731 732 733</DD> 734 735<DT><b><a name="always_bcc">always_bcc</a> 736(default: empty)</b></DT><DD> 737 738<p> 739Optional address that receives a "blind carbon copy" of each message 740that is received by the Postfix mail system. 741</p> 742 743<p> 744Note: if mail to the BCC address bounces it will be returned to 745the sender. 746</p> 747 748<p> Note: automatic BCC recipients are produced only for new mail. 749To avoid mailer loops, automatic BCC recipients are not generated 750after Postfix forwards mail internally, or after Postfix generates 751mail itself. </p> 752 753 754</DD> 755 756<DT><b><a name="anvil_rate_time_unit">anvil_rate_time_unit</a> 757(default: 60s)</b></DT><DD> 758 759<p> 760The time unit over which client connection rates and other rates 761are calculated. 762</p> 763 764<p> 765This feature is implemented by the <a href="anvil.8.html">anvil(8)</a> service which is available 766in Postfix version 2.2 and later. 767</p> 768 769<p> 770The default interval is relatively short. Because of the high 771frequency of updates, the <a href="anvil.8.html">anvil(8)</a> server uses volatile memory 772only. Thus, information is lost whenever the process terminates. 773</p> 774 775<p> 776Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 777The default time unit is s (seconds). 778</p> 779 780 781</DD> 782 783<DT><b><a name="anvil_status_update_time">anvil_status_update_time</a> 784(default: 600s)</b></DT><DD> 785 786<p> 787How frequently the <a href="anvil.8.html">anvil(8)</a> connection and rate limiting server 788logs peak usage information. 789</p> 790 791<p> 792This feature is available in Postfix 2.2 and later. 793</p> 794 795<p> 796Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 797The default time unit is s (seconds). 798</p> 799 800 801</DD> 802 803<DT><b><a name="append_at_myorigin">append_at_myorigin</a> 804(default: yes)</b></DT><DD> 805 806<p> 807With locally submitted mail, append the string "@$<a href="postconf.5.html#myorigin">myorigin</a>" to mail 808addresses without domain information. With remotely submitted mail, 809append the string "@$<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a>" instead. 810</p> 811 812<p> 813Note 1: this feature is enabled by default and must not be turned off. 814Postfix does not support domain-less addresses. 815</p> 816 817<p> Note 2: with Postfix version 2.2, message header address rewriting 818happens only when one of the following conditions is true: </p> 819 820<ul> 821 822<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 823 824<li> The message is received from a network client that matches 825$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 826 827<li> The message is received from the network, and the 828<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 829 830</ul> 831 832<p> To get the behavior before Postfix version 2.2, specify 833"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 834 835 836</DD> 837 838<DT><b><a name="append_dot_mydomain">append_dot_mydomain</a> 839(default: yes)</b></DT><DD> 840 841<p> 842With locally submitted mail, append the string ".$<a href="postconf.5.html#mydomain">mydomain</a>" to 843addresses that have no ".domain" information. With remotely submitted 844mail, append the string ".$<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a>" 845instead. 846</p> 847 848<p> 849Note 1: this feature is enabled by default. If disabled, users will not be 850able to send mail to "user@partialdomainname" but will have to 851specify full domain names instead. 852</p> 853 854<p> Note 2: with Postfix version 2.2, message header address rewriting 855happens only when one of the following conditions is true: </p> 856 857<ul> 858 859<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 860 861<li> The message is received from a network client that matches 862$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 863 864<li> The message is received from the network, and the 865<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 866 867</ul> 868 869<p> To get the behavior before Postfix version 2.2, specify 870"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 871 872 873</DD> 874 875<DT><b><a name="application_event_drain_time">application_event_drain_time</a> 876(default: 100s)</b></DT><DD> 877 878<p> 879How long the <a href="postkick.1.html">postkick(1)</a> command waits for a request to enter the 880server's input buffer before giving up. 881</p> 882 883<p> 884Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 885The default time unit is s (seconds). 886</p> 887 888<p> 889This feature is available in Postfix 2.1 and later. 890</p> 891 892 893</DD> 894 895<DT><b><a name="authorized_flush_users">authorized_flush_users</a> 896(default: static:anyone)</b></DT><DD> 897 898<p> 899List of users who are authorized to flush the queue. 900</p> 901 902<p> 903By default, all users are allowed to flush the queue. Access is 904always granted if the invoking user is the super-user or the 905$<a href="postconf.5.html#mail_owner">mail_owner</a> user. Otherwise, the real UID of the process is looked 906up in the system password file, and access is granted only if the 907corresponding login name is on the access list. The username 908"unknown" is used for processes whose real UID is not found in the 909password file. </p> 910 911<p> 912Specify a list of user names, "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns, 913separated by commas and/or whitespace. The list is matched left to 914right, and the search stops on the first match. A "/file/name" 915pattern is replaced 916by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a name 917matches a lookup key (the lookup result is ignored). Continue long 918lines by starting the next line with whitespace. Specify "!pattern" 919to exclude a name from the list. The form "!/file/name" is supported 920only in Postfix version 2.4 and later. </p> 921 922<p> 923This feature is available in Postfix 2.2 and later. 924</p> 925 926 927</DD> 928 929<DT><b><a name="authorized_mailq_users">authorized_mailq_users</a> 930(default: static:anyone)</b></DT><DD> 931 932<p> 933List of users who are authorized to view the queue. 934</p> 935 936<p> 937By default, all users are allowed to view the queue. Access is 938always granted if the invoking user is the super-user or the 939$<a href="postconf.5.html#mail_owner">mail_owner</a> user. Otherwise, the real UID of the process is looked 940up in the system password file, and access is granted only if the 941corresponding login name is on the access list. The username 942"unknown" is used for processes whose real UID is not found in the 943password file. </p> 944 945<p> 946Specify a list of user names, "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns, 947separated by commas and/or whitespace. The list is matched left to 948right, and the search stops on the first match. A "/file/name" 949pattern is replaced 950by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a name 951matches a lookup key (the lookup result is ignored). Continue long 952lines by starting the next line with whitespace. Specify "!pattern" 953to exclude a user name from the list. The form "!/file/name" is 954supported only in Postfix version 2.4 and later. </p> 955 956<p> 957This feature is available in Postfix 2.2 and later. 958</p> 959 960 961</DD> 962 963<DT><b><a name="authorized_submit_users">authorized_submit_users</a> 964(default: static:anyone)</b></DT><DD> 965 966<p> 967List of users who are authorized to submit mail with the <a href="sendmail.1.html">sendmail(1)</a> 968command (and with the privileged <a href="postdrop.1.html">postdrop(1)</a> helper command). 969</p> 970 971<p> 972By default, all users are allowed to submit mail. Otherwise, the 973real UID of the process is looked up in the system password file, 974and access is granted only if the corresponding login name is on 975the access list. The username "unknown" is used for processes 976whose real UID is not found in the password file. To deny mail 977submission access to all users specify an empty list. </p> 978 979<p> 980Specify a list of user names, "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns, 981separated by commas and/or whitespace. The list is matched left to right, 982and the search stops on the first match. A "/file/name" pattern is 983replaced by its contents; 984a "<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a name matches a lookup key 985(the lookup result is ignored). Continue long lines by starting the 986next line with whitespace. Specify "!pattern" to exclude a user 987name from the list. The form "!/file/name" is supported only in 988Postfix version 2.4 and later. </p> 989 990<p> 991Example: 992</p> 993 994<pre> 995<a href="postconf.5.html#authorized_submit_users">authorized_submit_users</a> = !www, static:all 996</pre> 997 998<p> 999This feature is available in Postfix 2.2 and later. 1000</p> 1001 1002 1003</DD> 1004 1005<DT><b><a name="authorized_verp_clients">authorized_verp_clients</a> 1006(default: $<a href="postconf.5.html#mynetworks">mynetworks</a>)</b></DT><DD> 1007 1008<p> What SMTP clients are allowed to specify the XVERP command. 1009This command requests that mail be delivered one recipient at a 1010time with a per recipient return address. </p> 1011 1012<p> By default, only trusted clients are allowed to specify XVERP. 1013</p> 1014 1015<p> This parameter was introduced with Postfix version 1.1. Postfix 1016version 2.1 renamed this parameter to <a href="postconf.5.html#smtpd_authorized_verp_clients">smtpd_authorized_verp_clients</a> 1017and changed the default to none. </p> 1018 1019<p> Specify a list of network/netmask patterns, separated by commas 1020and/or whitespace. The mask specifies the number of bits in the 1021network part of a host address. You can also specify hostnames or 1022.domain names (the initial dot causes the domain to match any name 1023below it), "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns. A "/file/name" 1024pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table 1025is matched when a table entry matches a lookup string (the lookup 1026result is ignored). Continue long lines by starting the next line 1027with whitespace. Specify "!pattern" to exclude an address or network 1028block from the list. The form "!/file/name" is supported only in 1029Postfix version 2.4 and later. </p> 1030 1031<p> Note: IP version 6 address information must be specified inside 1032<tt>[]</tt> in the <a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a> value, and in files 1033specified with "/file/name". IP version 6 addresses contain the 1034":" character, and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" 1035pattern. </p> 1036 1037 1038</DD> 1039 1040<DT><b><a name="backwards_bounce_logfile_compatibility">backwards_bounce_logfile_compatibility</a> 1041(default: yes)</b></DT><DD> 1042 1043<p> 1044Produce additional <a href="bounce.8.html">bounce(8)</a> logfile records that can be read by 1045Postfix versions before 2.0. The current and more extensible "name = 1046value" format is needed in order to implement more sophisticated 1047functionality. 1048</p> 1049 1050<p> 1051This feature is available in Postfix 2.1 and later. 1052</p> 1053 1054 1055</DD> 1056 1057<DT><b><a name="berkeley_db_create_buffer_size">berkeley_db_create_buffer_size</a> 1058(default: 16777216)</b></DT><DD> 1059 1060<p> 1061The per-table I/O buffer size for programs that create Berkeley DB 1062hash or btree tables. Specify a byte count. 1063</p> 1064 1065<p> 1066This feature is available in Postfix 2.0 and later. 1067</p> 1068 1069 1070</DD> 1071 1072<DT><b><a name="berkeley_db_read_buffer_size">berkeley_db_read_buffer_size</a> 1073(default: 131072)</b></DT><DD> 1074 1075<p> 1076The per-table I/O buffer size for programs that read Berkeley DB 1077hash or btree tables. Specify a byte count. 1078</p> 1079 1080<p> 1081This feature is available in Postfix 2.0 and later. 1082</p> 1083 1084 1085</DD> 1086 1087<DT><b><a name="best_mx_transport">best_mx_transport</a> 1088(default: empty)</b></DT><DD> 1089 1090<p> 1091Where the Postfix SMTP client should deliver mail when it detects 1092a "mail loops back to myself" error condition. This happens when 1093the local MTA is the best SMTP mail exchanger for a destination 1094not listed in $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>, $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, 1095$<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, or $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>. By default, 1096the Postfix SMTP client returns such mail as undeliverable. 1097</p> 1098 1099<p> 1100Specify, for example, "<a href="postconf.5.html#best_mx_transport">best_mx_transport</a> = local" to pass the mail 1101from the Postfix SMTP client to the <a href="local.8.html">local(8)</a> delivery agent. You 1102can specify 1103any message delivery "transport" or "transport:nexthop" that is 1104defined in the <a href="master.5.html">master.cf</a> file. See the <a href="transport.5.html">transport(5)</a> manual page 1105for the syntax and meaning of "transport" or "transport:nexthop". 1106</p> 1107 1108<p> 1109However, this feature is expensive because it ties up a Postfix 1110SMTP client process while the <a href="local.8.html">local(8)</a> delivery agent is doing its 1111work. It is more efficient (for Postfix) to list all <a href="VIRTUAL_README.html#canonical">hosted domains</a> 1112in a table or database. 1113</p> 1114 1115 1116</DD> 1117 1118<DT><b><a name="biff">biff</a> 1119(default: yes)</b></DT><DD> 1120 1121<p> 1122Whether or not to use the local <a href="postconf.5.html#biff">biff</a> service. This service sends 1123"new mail" notifications to users who have requested new mail 1124notification with the UNIX command "<a href="postconf.5.html#biff">biff</a> y". 1125</p> 1126 1127<p> 1128For compatibility reasons this feature is on by default. On systems 1129with lots of interactive users, the <a href="postconf.5.html#biff">biff</a> service can be a performance 1130drain. Specify "<a href="postconf.5.html#biff">biff</a> = no" in <a href="postconf.5.html">main.cf</a> to disable. 1131</p> 1132 1133 1134</DD> 1135 1136<DT><b><a name="body_checks">body_checks</a> 1137(default: empty)</b></DT><DD> 1138 1139<p> Optional lookup tables for content inspection as specified in 1140the <a href="header_checks.5.html">body_checks(5)</a> manual page. </p> 1141 1142<p> Note: with Postfix versions before 2.0, these rules inspect 1143all content after the primary message headers. </p> 1144 1145 1146</DD> 1147 1148<DT><b><a name="body_checks_size_limit">body_checks_size_limit</a> 1149(default: 51200)</b></DT><DD> 1150 1151<p> 1152How much text in a message body segment (or attachment, if you 1153prefer to use that term) is subjected to <a href="postconf.5.html#body_checks">body_checks</a> inspection. 1154The amount of text is limited to avoid scanning huge attachments. 1155</p> 1156 1157<p> 1158This feature is available in Postfix 2.0 and later. 1159</p> 1160 1161 1162</DD> 1163 1164<DT><b><a name="bounce_notice_recipient">bounce_notice_recipient</a> 1165(default: postmaster)</b></DT><DD> 1166 1167<p> 1168The recipient of postmaster notifications with the message headers 1169of mail that Postfix did not deliver and of SMTP conversation 1170transcripts of mail that Postfix did not receive. This feature is 1171enabled with the <a href="postconf.5.html#notify_classes">notify_classes</a> parameter. </p> 1172 1173 1174</DD> 1175 1176<DT><b><a name="bounce_queue_lifetime">bounce_queue_lifetime</a> 1177(default: 5d)</b></DT><DD> 1178 1179<p> 1180The maximal time a bounce message is queued before it is considered 1181undeliverable. By default, this is the same as the queue life time 1182for regular mail. 1183</p> 1184 1185<p> 1186Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 1187The default time unit is d (days). 1188</p> 1189 1190<p> 1191Specify 0 when mail delivery should be tried only once. 1192</p> 1193 1194<p> 1195This feature is available in Postfix 2.1 and later. 1196</p> 1197 1198 1199</DD> 1200 1201<DT><b><a name="bounce_service_name">bounce_service_name</a> 1202(default: bounce)</b></DT><DD> 1203 1204<p> 1205The name of the <a href="bounce.8.html">bounce(8)</a> service. This service maintains a record 1206of failed delivery attempts and generates non-delivery notifications. 1207</p> 1208 1209<p> 1210This feature is available in Postfix 2.0 and later. 1211</p> 1212 1213 1214</DD> 1215 1216<DT><b><a name="bounce_size_limit">bounce_size_limit</a> 1217(default: 50000)</b></DT><DD> 1218 1219<p> The maximal amount of original message text that is sent in a 1220non-delivery notification. Specify a byte count. A message is 1221returned as either message/rfc822 (the complete original) or as 1222text/rfc822-headers (the headers only). With Postfix version 2.4 1223and earlier, a message is always returned as message/rfc822 and is 1224truncated when it exceeds the size limit. 1225</p> 1226 1227<p> Notes: </p> 1228 1229<ul> 1230 1231<li> <p> If you increase this limit, then you should increase the 1232<a href="postconf.5.html#mime_nesting_limit">mime_nesting_limit</a> value proportionally. </p> 1233 1234<li> <p> Be careful when making changes. Excessively large values 1235will result in the loss of non-delivery notifications, when a bounce 1236message size exceeds a local or remote MTA's message size limit. 1237</p> 1238 1239</ul> 1240 1241 1242</DD> 1243 1244<DT><b><a name="bounce_template_file">bounce_template_file</a> 1245(default: empty)</b></DT><DD> 1246 1247<p> Pathname of a configuration file with bounce message templates. 1248These override the built-in templates of delivery status notification 1249(DSN) messages for undeliverable mail, for delayed mail, successful 1250delivery, or delivery verification. The <a href="bounce.5.html">bounce(5)</a> manual page 1251describes how to edit and test template files. </p> 1252 1253<p> Template message body text may contain $name references to 1254Postfix configuration parameters. The result of $name expansion can 1255be previewed with "<b>postconf -b <i>file_name</i></b>" before the file 1256is placed into the Postfix configuration directory. </p> 1257 1258<p> This feature is available in Postfix 2.3 and later. </p> 1259 1260 1261</DD> 1262 1263<DT><b><a name="broken_sasl_auth_clients">broken_sasl_auth_clients</a> 1264(default: no)</b></DT><DD> 1265 1266<p> 1267Enable inter-operability with SMTP clients that implement an obsolete 1268version of the AUTH command (<a href="http://tools.ietf.org/html/rfc4954">RFC 4954</a>). Examples of such clients 1269are MicroSoft Outlook Express version 4 and MicroSoft Exchange 1270version 5.0. 1271</p> 1272 1273<p> 1274Specify "<a href="postconf.5.html#broken_sasl_auth_clients">broken_sasl_auth_clients</a> = yes" to have Postfix advertise 1275AUTH support in a non-standard way. 1276</p> 1277 1278 1279</DD> 1280 1281<DT><b><a name="canonical_classes">canonical_classes</a> 1282(default: envelope_sender, envelope_recipient, header_sender, header_recipient)</b></DT><DD> 1283 1284<p> What addresses are subject to <a href="postconf.5.html#canonical_maps">canonical_maps</a> address mapping. 1285By default, <a href="postconf.5.html#canonical_maps">canonical_maps</a> address mapping is applied to envelope 1286sender and recipient addresses, and to header sender and header 1287recipient addresses. </p> 1288 1289<p> Specify one or more of: envelope_sender, envelope_recipient, 1290header_sender, header_recipient </p> 1291 1292<p> This feature is available in Postfix 2.2 and later. </p> 1293 1294 1295</DD> 1296 1297<DT><b><a name="canonical_maps">canonical_maps</a> 1298(default: empty)</b></DT><DD> 1299 1300<p> 1301Optional address mapping lookup tables for message headers and 1302envelopes. The mapping is applied to both sender and recipient 1303addresses, in both envelopes and in headers, as controlled 1304with the <a href="postconf.5.html#canonical_classes">canonical_classes</a> parameter. This is typically used 1305to clean up dirty addresses from legacy mail systems, or to replace 1306login names by Firstname.Lastname. The table format and lookups 1307are documented in <a href="canonical.5.html">canonical(5)</a>. For an overview of Postfix address 1308manipulations see the <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a> document. 1309</p> 1310 1311<p> 1312If you use this feature, run "<b>postmap /etc/postfix/canonical</b>" to 1313build the necessary DBM or DB file after every change. The changes 1314will become visible after a minute or so. Use "<b>postfix reload</b>" 1315to eliminate the delay. 1316</p> 1317 1318<p> Note: with Postfix version 2.2, message header address mapping 1319happens only when message header address rewriting is enabled: </p> 1320 1321<ul> 1322 1323<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 1324 1325<li> The message is received from a network client that matches 1326$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 1327 1328<li> The message is received from the network, and the 1329<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 1330 1331</ul> 1332 1333<p> To get the behavior before Postfix version 2.2, specify 1334"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 1335 1336<p> 1337Examples: 1338</p> 1339 1340<pre> 1341<a href="postconf.5.html#canonical_maps">canonical_maps</a> = dbm:/etc/postfix/canonical 1342<a href="postconf.5.html#canonical_maps">canonical_maps</a> = hash:/etc/postfix/canonical 1343</pre> 1344 1345 1346</DD> 1347 1348<DT><b><a name="cleanup_service_name">cleanup_service_name</a> 1349(default: cleanup)</b></DT><DD> 1350 1351<p> 1352The name of the <a href="cleanup.8.html">cleanup(8)</a> service. This service rewrites addresses 1353into the standard form, and performs <a href="canonical.5.html">canonical(5)</a> address mapping 1354and <a href="virtual.5.html">virtual(5)</a> aliasing. 1355</p> 1356 1357<p> 1358This feature is available in Postfix 2.0 and later. 1359</p> 1360 1361 1362</DD> 1363 1364<DT><b><a name="command_directory">command_directory</a> 1365(default: see "postconf -d" output)</b></DT><DD> 1366 1367<p> 1368The location of all postfix administrative commands. 1369</p> 1370 1371 1372</DD> 1373 1374<DT><b><a name="command_execution_directory">command_execution_directory</a> 1375(default: empty)</b></DT><DD> 1376 1377<p> The <a href="local.8.html">local(8)</a> delivery agent working directory for delivery to 1378external command. Failure to change directory causes the delivery 1379to be deferred. </p> 1380 1381<p> The following $name expansions are done on <a href="postconf.5.html#command_execution_directory">command_execution_directory</a> 1382before the directory is changed. Expansion happens in the context 1383of the delivery request. The result of $name expansion is filtered 1384with the character set that is specified with the 1385<a href="postconf.5.html#execution_directory_expansion_filter">execution_directory_expansion_filter</a> parameter. </p> 1386 1387<dl> 1388 1389<dt><b>$user</b></dt> 1390 1391<dd>The recipient's username. </dd> 1392 1393<dt><b>$shell</b></dt> 1394 1395<dd>The recipient's login shell pathname. </dd> 1396 1397<dt><b>$home</b></dt> 1398 1399<dd>The recipient's home directory. </dd> 1400 1401<dt><b>$recipient</b></dt> 1402 1403<dd>The full recipient address. </dd> 1404 1405<dt><b>$extension</b></dt> 1406 1407<dd>The optional recipient address extension. </dd> 1408 1409<dt><b>$domain</b></dt> 1410 1411<dd>The recipient domain. </dd> 1412 1413<dt><b>$local</b></dt> 1414 1415<dd>The entire recipient localpart. </dd> 1416 1417<dt><b>$<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a></b></dt> 1418 1419<dd>The system-wide recipient address extension delimiter. </dd> 1420 1421<dt><b>${name?value}</b></dt> 1422 1423<dd>Expands to <i>value</i> when <i>$name</i> is non-empty. </dd> 1424 1425<dt><b>${name:value}</b></dt> 1426 1427<dd>Expands to <i>value</i> when <i>$name</i> is empty. </dd> 1428 1429</dl> 1430 1431<p> 1432Instead of $name you can also specify ${name} or $(name). 1433</p> 1434 1435<p> This feature is available in Postfix 2.2 and later. </p> 1436 1437 1438</DD> 1439 1440<DT><b><a name="command_expansion_filter">command_expansion_filter</a> 1441(default: see "postconf -d" output)</b></DT><DD> 1442 1443<p> 1444Restrict the characters that the <a href="local.8.html">local(8)</a> delivery agent allows in 1445$name expansions of $<a href="postconf.5.html#mailbox_command">mailbox_command</a> and $<a href="postconf.5.html#command_execution_directory">command_execution_directory</a>. 1446Characters outside the 1447allowed set are replaced by underscores. 1448</p> 1449 1450 1451</DD> 1452 1453<DT><b><a name="command_time_limit">command_time_limit</a> 1454(default: 1000s)</b></DT><DD> 1455 1456<p> 1457Time limit for delivery to external commands. This limit is used 1458by the <a href="local.8.html">local(8)</a> delivery agent, and is the default time limit for 1459delivery by the <a href="pipe.8.html">pipe(8)</a> delivery agent. 1460</p> 1461 1462<p> 1463Note: if you set this time limit to a large value you must update the 1464global <a href="postconf.5.html#ipc_timeout">ipc_timeout</a> parameter as well. 1465</p> 1466 1467 1468</DD> 1469 1470<DT><b><a name="config_directory">config_directory</a> 1471(default: see "postconf -d" output)</b></DT><DD> 1472 1473<p> The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> 1474configuration files. This can be overruled via the following 1475mechanisms: </p> 1476 1477<ul> 1478 1479<li> <p> The MAIL_CONFIG environment variable (daemon processes 1480and commands). </p> 1481 1482<li> <p> The "-c" command-line option (commands only). </p> 1483 1484</ul> 1485 1486<p> With Postfix command that run with set-gid privileges, a 1487<a href="postconf.5.html#config_directory">config_directory</a> override requires either root privileges, or it 1488requires that the directory is listed with the <a href="postconf.5.html#alternate_config_directories">alternate_config_directories</a> 1489parameter in the default <a href="postconf.5.html">main.cf</a> file. </p> 1490 1491 1492</DD> 1493 1494<DT><b><a name="connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> 1495(default: 5s)</b></DT><DD> 1496 1497<p> Time limit for connection cache connect, send or receive 1498operations. The time limit is enforced in the client. </p> 1499 1500<p> This feature is available in Postfix 2.3 and later. </p> 1501 1502 1503</DD> 1504 1505<DT><b><a name="connection_cache_service_name">connection_cache_service_name</a> 1506(default: scache)</b></DT><DD> 1507 1508<p> The name of the <a href="scache.8.html">scache(8)</a> connection cache service. This service 1509maintains a limited pool of cached sessions. </p> 1510 1511<p> This feature is available in Postfix 2.2 and later. </p> 1512 1513 1514</DD> 1515 1516<DT><b><a name="connection_cache_status_update_time">connection_cache_status_update_time</a> 1517(default: 600s)</b></DT><DD> 1518 1519<p> How frequently the <a href="scache.8.html">scache(8)</a> server logs usage statistics with 1520connection cache hit and miss rates for logical destinations and for 1521physical endpoints. </p> 1522 1523 1524</DD> 1525 1526<DT><b><a name="connection_cache_ttl_limit">connection_cache_ttl_limit</a> 1527(default: 2s)</b></DT><DD> 1528 1529<p> The maximal time-to-live value that the <a href="scache.8.html">scache(8)</a> connection 1530cache server 1531allows. Requests that specify a larger TTL will be stored with the 1532maximum allowed TTL. The purpose of this additional control is to 1533protect the infrastructure against careless people. The cache TTL 1534is already bounded by $<a href="postconf.5.html#max_idle">max_idle</a>. </p> 1535 1536 1537</DD> 1538 1539<DT><b><a name="content_filter">content_filter</a> 1540(default: empty)</b></DT><DD> 1541 1542<p> After the message is queued, send the entire message to the 1543specified <i>transport:destination</i>. The <i>transport</i> name 1544specifies the first field of a mail delivery agent definition in 1545<a href="master.5.html">master.cf</a>; the syntax of the next-hop <i>destination</i> is described 1546in the manual page of the corresponding delivery agent. More 1547information about external content filters is in the Postfix 1548<a href="FILTER_README.html">FILTER_README</a> file. </p> 1549 1550<p> Notes: </p> 1551 1552<ul> 1553 1554<li> <p> This setting has lower precedence than a FILTER action 1555that is specified in an <a href="access.5.html">access(5)</a>, <a href="header_checks.5.html">header_checks(5)</a> or <a href="header_checks.5.html">body_checks(5)</a> 1556table. </p> 1557 1558<li> <p> The meaning of an empty next-hop filter <i>destination</i> 1559is version dependent. Postfix 2.7 and later will use the recipient 1560domain; earlier versions will use $<a href="postconf.5.html#myhostname">myhostname</a>. Specify 1561"<a href="postconf.5.html#default_filter_nexthop">default_filter_nexthop</a> = $<a href="postconf.5.html#myhostname">myhostname</a>" for compatibility with Postfix 15622.6 or earlier, or specify a <a href="postconf.5.html#content_filter">content_filter</a> value with an explicit 1563next-hop <i>destination</i>. </p> 1564 1565</ul> 1566 1567 1568</DD> 1569 1570<DT><b><a name="cyrus_sasl_config_path">cyrus_sasl_config_path</a> 1571(default: empty)</b></DT><DD> 1572 1573<p> Search path for Cyrus SASL application configuration files, 1574currently used only to locate the $<a href="postconf.5.html#smtpd_sasl_path">smtpd_sasl_path</a>.conf file. 1575Specify zero or more directories separated by a colon character, 1576or an empty value to use Cyrus SASL's built-in search path. </p> 1577 1578<p> This feature is available in Postfix 2.5 and later when compiled 1579with Cyrus SASL 2.1.22 or later. </p> 1580 1581 1582</DD> 1583 1584<DT><b><a name="daemon_directory">daemon_directory</a> 1585(default: see "postconf -d" output)</b></DT><DD> 1586 1587<p> 1588The directory with Postfix support programs and daemon programs. 1589These should not be invoked directly by humans. The directory must 1590be owned by root. 1591</p> 1592 1593 1594</DD> 1595 1596<DT><b><a name="daemon_timeout">daemon_timeout</a> 1597(default: 18000s)</b></DT><DD> 1598 1599<p> How much time a Postfix daemon process may take to handle a 1600request before it is terminated by a built-in watchdog timer. </p> 1601 1602<p> 1603Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 1604The default time unit is s (seconds). 1605</p> 1606 1607 1608</DD> 1609 1610<DT><b><a name="data_directory">data_directory</a> 1611(default: see "postconf -d" output)</b></DT><DD> 1612 1613<p> The directory with Postfix-writable data files (for example: 1614caches, pseudo-random numbers). This directory must be owned by 1615the <a href="postconf.5.html#mail_owner">mail_owner</a> account, and must not be shared with non-Postfix 1616software. </p> 1617 1618<p> This feature is available in Postfix 2.5 and later. </p> 1619 1620 1621</DD> 1622 1623<DT><b><a name="debug_peer_level">debug_peer_level</a> 1624(default: 2)</b></DT><DD> 1625 1626<p> The increment in verbose logging level when a remote client or 1627server matches a pattern in the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter. </p> 1628 1629 1630</DD> 1631 1632<DT><b><a name="debug_peer_list">debug_peer_list</a> 1633(default: empty)</b></DT><DD> 1634 1635<p> Optional list of remote client or server hostname or network 1636address patterns that cause the verbose logging level to increase 1637by the amount specified in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>. </p> 1638 1639<p> Specify domain names, network/netmask patterns, "/file/name" 1640patterns or "<a href="DATABASE_README.html">type:table</a>" lookup tables. The right-hand side result 1641from "<a href="DATABASE_README.html">type:table</a>" lookups is ignored. </p> 1642 1643<p> Pattern matching of domain names is controlled by the 1644<a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> parameter. </p> 1645 1646<p> 1647Examples: 1648</p> 1649 1650<pre> 1651<a href="postconf.5.html#debug_peer_list">debug_peer_list</a> = 127.0.0.1 1652<a href="postconf.5.html#debug_peer_list">debug_peer_list</a> = example.com 1653</pre> 1654 1655 1656</DD> 1657 1658<DT><b><a name="debugger_command">debugger_command</a> 1659(default: empty)</b></DT><DD> 1660 1661<p> 1662The external command to execute when a Postfix daemon program is 1663invoked with the -D option. 1664</p> 1665 1666<p> 1667Use "command .. & sleep 5" so that the debugger can attach before 1668the process marches on. If you use an X-based debugger, be sure to 1669set up your XAUTHORITY environment variable before starting Postfix. 1670</p> 1671 1672<p> 1673Example: 1674</p> 1675 1676<pre> 1677<a href="postconf.5.html#debugger_command">debugger_command</a> = 1678 PATH=/usr/bin:/usr/X11R6/bin 1679 ddd $<a href="postconf.5.html#daemon_directory">daemon_directory</a>/$<a href="postconf.5.html#process_name">process_name</a> $<a href="postconf.5.html#process_id">process_id</a> & sleep 5 1680</pre> 1681 1682 1683</DD> 1684 1685<DT><b><a name="default_database_type">default_database_type</a> 1686(default: see "postconf -d" output)</b></DT><DD> 1687 1688<p> 1689The default database type for use in <a href="newaliases.1.html">newaliases(1)</a>, <a href="postalias.1.html">postalias(1)</a> 1690and <a href="postmap.1.html">postmap(1)</a> commands. On many UNIX systems the default type is 1691either <b>dbm</b> or <b>hash</b>. The default setting is frozen 1692when the Postfix system is built. 1693</p> 1694 1695<p> 1696Examples: 1697</p> 1698 1699<pre> 1700<a href="postconf.5.html#default_database_type">default_database_type</a> = hash 1701<a href="postconf.5.html#default_database_type">default_database_type</a> = dbm 1702</pre> 1703 1704 1705</DD> 1706 1707<DT><b><a name="default_delivery_slot_cost">default_delivery_slot_cost</a> 1708(default: 5)</b></DT><DD> 1709 1710<p> 1711How often the Postfix queue manager's scheduler is allowed to 1712preempt delivery of one message with another. 1713</p> 1714 1715<p> 1716Each transport maintains a so-called "available delivery slot counter" 1717for each message. One message can be preempted by another one when 1718the other message can be delivered using no more delivery slots 1719(i.e., invocations of delivery agents) than the current message 1720counter has accumulated (or will eventually accumulate - see about 1721slot loans below). This parameter controls how often is the counter 1722incremented - it happens after each <a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> 1723recipients have been delivered. 1724</p> 1725 1726<p> 1727The cost of 0 is used to disable the preempting scheduling completely. 1728The minimum value the scheduling algorithm can use is 2 - use it 1729if you want to maximize the message throughput rate. Although there 1730is no maximum, it doesn't make much sense to use values above say 173150. 1732</p> 1733 1734<p> 1735The only reason why the value of 2 is not the default is the way 1736this parameter affects the delivery of mailing-list mail. In the 1737worst case, their delivery can take somewhere between (cost+1/cost) 1738and (cost/cost-1) times more than if the preemptive scheduler was 1739disabled. The default value of 5 turns out to provide reasonable 1740message response times while making sure the mailing-list deliveries 1741are not extended by more than 20-25 percent even in the worst case. 1742</p> 1743 1744<p> Use <a href="postconf.5.html#transport_delivery_slot_cost"><i>transport</i>_delivery_slot_cost</a> to specify a 1745transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1746name of the message delivery transport. 1747</p> 1748 1749<p> 1750Examples: 1751</p> 1752 1753<pre> 1754<a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> = 0 1755<a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> = 2 1756</pre> 1757 1758 1759</DD> 1760 1761<DT><b><a name="default_delivery_slot_discount">default_delivery_slot_discount</a> 1762(default: 50)</b></DT><DD> 1763 1764<p> 1765The default value for transport-specific _delivery_slot_discount 1766settings. 1767</p> 1768 1769<p> 1770This parameter speeds up the moment when a message preemption can 1771happen. Instead of waiting until the full amount of delivery slots 1772required is available, the preemption can happen when 1773transport_delivery_slot_discount percent of the required amount 1774plus transport_delivery_slot_loan still remains to be accumulated. 1775Note that the full amount will still have to be accumulated before 1776another preemption can take place later. 1777</p> 1778 1779<p> Use <a href="postconf.5.html#transport_delivery_slot_discount"><i>transport</i>_delivery_slot_discount</a> to specify a 1780transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1781name of the message delivery transport. 1782</p> 1783 1784 1785</DD> 1786 1787<DT><b><a name="default_delivery_slot_loan">default_delivery_slot_loan</a> 1788(default: 3)</b></DT><DD> 1789 1790<p> 1791The default value for transport-specific _delivery_slot_loan 1792settings. 1793</p> 1794 1795<p> 1796This parameter speeds up the moment when a message preemption can 1797happen. Instead of waiting until the full amount of delivery slots 1798required is available, the preemption can happen when 1799transport_delivery_slot_discount percent of the required amount 1800plus transport_delivery_slot_loan still remains to be accumulated. 1801Note that the full amount will still have to be accumulated before 1802another preemption can take place later. 1803</p> 1804 1805<p> Use <a href="postconf.5.html#transport_delivery_slot_loan"><i>transport</i>_delivery_slot_loan</a> to specify a 1806transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1807name of the message delivery transport. 1808</p> 1809 1810 1811</DD> 1812 1813<DT><b><a name="default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a> 1814(default: 1)</b></DT><DD> 1815 1816<p> How many pseudo-cohorts must suffer connection or handshake 1817failure before a specific destination is considered unavailable 1818(and further delivery is suspended). Specify zero to disable this 1819feature. A destination's pseudo-cohort failure count is reset each 1820time a delivery completes without connection or handshake failure 1821for that specific destination. </p> 1822 1823<p> A pseudo-cohort is the number of deliveries equal to a destination's 1824delivery concurrency. </p> 1825 1826<p> Use <a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit"><i>transport</i>_destination_concurrency_failed_cohort_limit</a> to specify 1827a transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1828name of the message delivery transport. </p> 1829 1830<p> This feature is available in Postfix 2.5. The default setting 1831is compatible with earlier Postfix versions. </p> 1832 1833 1834</DD> 1835 1836<DT><b><a name="default_destination_concurrency_limit">default_destination_concurrency_limit</a> 1837(default: 20)</b></DT><DD> 1838 1839<p> 1840The default maximal number of parallel deliveries to the same 1841destination. This is the default limit for delivery via the <a href="lmtp.8.html">lmtp(8)</a>, 1842<a href="pipe.8.html">pipe(8)</a>, <a href="smtp.8.html">smtp(8)</a> and <a href="virtual.8.html">virtual(8)</a> delivery agents. 1843With per-destination recipient limit > 1, a destination is a domain, 1844otherwise it is a recipient. 1845</p> 1846 1847<p> Use <a href="postconf.5.html#transport_destination_concurrency_limit"><i>transport</i>_destination_concurrency_limit</a> to specify a 1848transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1849name of the message delivery transport. 1850</p> 1851 1852 1853</DD> 1854 1855<DT><b><a name="default_destination_concurrency_negative_feedback">default_destination_concurrency_negative_feedback</a> 1856(default: 1)</b></DT><DD> 1857 1858<p> The per-destination amount of delivery concurrency negative 1859feedback, after a delivery completes with a connection or handshake 1860failure. Feedback values are in the range 0..1 inclusive. With 1861negative feedback, concurrency is decremented at the beginning of 1862a sequence of length 1/feedback. This is unlike positive feedback, 1863where concurrency is incremented at the end of a sequence of length 18641/feedback. </p> 1865 1866<p> As of Postfix version 2.5, negative feedback cannot reduce 1867delivery concurrency to zero. Instead, a destination is marked 1868dead (further delivery suspended) after the failed pseudo-cohort 1869count reaches $<a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a> 1870(or $<a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit"><i>transport</i>_destination_concurrency_failed_cohort_limit</a>). 1871To make the scheduler completely immune to connection or handshake 1872failures, specify a zero feedback value and a zero failed pseudo-cohort 1873limit. </p> 1874 1875<p> Specify one of the following forms: </p> 1876 1877<dl> 1878 1879<dt> <b><i>number</i> </b> </dt> 1880 1881<dt> <b><i>number</i> / <i>number</i> </b> </dt> 1882 1883<dd> Constant feedback. The value must be in the range 0..1 inclusive. 1884The default setting of "1" is compatible with Postfix versions 1885before 2.5, where a destination's delivery concurrency is throttled 1886down to zero (and further delivery suspended) after a single failed 1887pseudo-cohort. </dd> 1888 1889<dt> <b><i>number</i> / concurrency </b> </dt> 1890 1891<dd> Variable feedback of "<i>number</i> / (delivery concurrency)". 1892The <i>number</i> must be in the range 0..1 inclusive. With 1893<i>number</i> equal to "1", a destination's delivery concurrency 1894is decremented by 1 after each failed pseudo-cohort. </dd> 1895 1896</dl> 1897 1898<p> A pseudo-cohort is the number of deliveries equal to a destination's 1899delivery concurrency. </p> 1900 1901<p> Use <a href="postconf.5.html#transport_destination_concurrency_negative_feedback"><i>transport</i>_destination_concurrency_negative_feedback</a> 1902to specify a transport-specific override, where <i>transport</i> 1903is the <a href="master.5.html">master.cf</a> 1904name of the message delivery transport. </p> 1905 1906<p> This feature is available in Postfix 2.5. The default setting 1907is compatible with earlier Postfix versions. </p> 1908 1909 1910</DD> 1911 1912<DT><b><a name="default_destination_concurrency_positive_feedback">default_destination_concurrency_positive_feedback</a> 1913(default: 1)</b></DT><DD> 1914 1915<p> The per-destination amount of delivery concurrency positive 1916feedback, after a delivery completes without connection or handshake 1917failure. Feedback values are in the range 0..1 inclusive. The 1918concurrency increases until it reaches the per-destination maximal 1919concurrency limit. With positive feedback, concurrency is incremented 1920at the end of a sequence with length 1/feedback. This is unlike 1921negative feedback, where concurrency is decremented at the start 1922of a sequence of length 1/feedback. </p> 1923 1924<p> Specify one of the following forms: </p> 1925 1926<dl> 1927 1928<dt> <b><i>number</i> </b> </dt> 1929 1930<dt> <b><i>number</i> / <i>number</i> </b> </dt> 1931 1932<dd> Constant feedback. The value must be in the range 0..1 1933inclusive. The default setting of "1" is compatible with Postfix 1934versions before 2.5, where a destination's delivery concurrency 1935doubles after each successful pseudo-cohort. </dd> 1936 1937<dt> <b><i>number</i> / concurrency </b> </dt> 1938 1939<dd> Variable feedback of "<i>number</i> / (delivery concurrency)". 1940The <i>number</i> must be in the range 0..1 inclusive. With 1941<i>number</i> equal to "1", a destination's delivery concurrency 1942is incremented by 1 after each successful pseudo-cohort. </dd> 1943 1944</dl> 1945 1946<p> A pseudo-cohort is the number of deliveries equal to a destination's 1947delivery concurrency. </p> 1948 1949<p> Use <a href="postconf.5.html#transport_destination_concurrency_positive_feedback"><i>transport</i>_destination_concurrency_positive_feedback</a> 1950to specify a transport-specific override, where <i>transport</i> 1951is the <a href="master.5.html">master.cf</a> name of the message delivery transport. </p> 1952 1953<p> This feature is available in Postfix 2.5 and later. </p> 1954 1955 1956</DD> 1957 1958<DT><b><a name="default_destination_rate_delay">default_destination_rate_delay</a> 1959(default: 0s)</b></DT><DD> 1960 1961<p> The default amount of delay that is inserted between individual 1962deliveries to the same destination; with per-destination recipient 1963limit > 1, a destination is a domain, otherwise it is a recipient. 1964</p> 1965 1966<p> To enable the delay, specify a non-zero time value (an integral 1967value plus an optional one-letter suffix that specifies the time 1968unit). </p> 1969 1970<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 1971(weeks). The default time unit is s (seconds). </p> 1972 1973<p> NOTE: the delay is enforced by the queue manager. The delay 1974timer state does not survive "<b>postfix reload</b>" or "<b>postfix 1975stop</b>". 1976</p> 1977 1978<p> Use <a href="postconf.5.html#transport_destination_rate_delay"><i>transport</i>_destination_rate_delay</a> to specify a 1979transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 1980name of the message delivery transport. 1981</p> 1982 1983<p> NOTE: with a non-zero _destination_rate_delay, specify a 1984<a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit"><i>transport</i>_destination_concurrency_failed_cohort_limit</a> of 10 1985or more to prevent Postfix from deferring all mail for the same 1986destination after only one connection or handshake error. </p> 1987 1988<p> This feature is available in Postfix 2.5 and later. </p> 1989 1990 1991</DD> 1992 1993<DT><b><a name="default_destination_recipient_limit">default_destination_recipient_limit</a> 1994(default: 50)</b></DT><DD> 1995 1996<p> 1997The default maximal number of recipients per message delivery. 1998This is the default limit for delivery via the <a href="lmtp.8.html">lmtp(8)</a>, <a href="pipe.8.html">pipe(8)</a>, 1999<a href="smtp.8.html">smtp(8)</a> and <a href="virtual.8.html">virtual(8)</a> delivery agents. 2000</p> 2001 2002<p> Setting this parameter to a value of 1 changes the meaning of 2003the corresponding per-destination concurrency limit from concurrency 2004per domain into concurrency per recipient. </p> 2005 2006<p> Use <a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a> to specify a 2007transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2008name of the message delivery transport. 2009</p> 2010 2011 2012</DD> 2013 2014<DT><b><a name="default_extra_recipient_limit">default_extra_recipient_limit</a> 2015(default: 1000)</b></DT><DD> 2016 2017<p> 2018The default value for the extra per-transport limit imposed on the 2019number of in-memory recipients. This extra recipient space is 2020reserved for the cases when the Postfix queue manager's scheduler 2021preempts one message with another and suddenly needs some extra 2022recipients slots for the chosen message in order to avoid performance 2023degradation. 2024</p> 2025 2026<p> Use <a href="postconf.5.html#transport_extra_recipient_limit"><i>transport</i>_extra_recipient_limit</a> to specify a 2027transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2028name of the message delivery transport. 2029</p> 2030 2031 2032</DD> 2033 2034<DT><b><a name="default_filter_nexthop">default_filter_nexthop</a> 2035(default: empty)</b></DT><DD> 2036 2037<p> When a <a href="postconf.5.html#content_filter">content_filter</a> or FILTER request specifies no explicit 2038next-hop destination, use $<a href="postconf.5.html#default_filter_nexthop">default_filter_nexthop</a> instead; when 2039that value is empty, use the domain in the recipient address. 2040Specify "<a href="postconf.5.html#default_filter_nexthop">default_filter_nexthop</a> = $<a href="postconf.5.html#myhostname">myhostname</a>" for compatibility 2041with Postfix version 2.6 and earlier, or specify an explicit next-hop 2042destination with each <a href="postconf.5.html#content_filter">content_filter</a> value or FILTER action. </p> 2043 2044<p> This feature is available in Postfix 2.7 and later. </p> 2045 2046 2047</DD> 2048 2049<DT><b><a name="default_minimum_delivery_slots">default_minimum_delivery_slots</a> 2050(default: 3)</b></DT><DD> 2051 2052<p> 2053How many recipients a message must have in order to invoke the 2054Postfix queue manager's scheduling algorithm at all. Messages 2055which would never accumulate at least this many delivery slots 2056(subject to slot cost parameter as well) are never preempted. 2057</p> 2058 2059<p> Use <a href="postconf.5.html#transport_minimum_delivery_slots"><i>transport</i>_minimum_delivery_slots</a> to specify a 2060transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2061name of the message delivery transport. 2062</p> 2063 2064 2065</DD> 2066 2067<DT><b><a name="default_privs">default_privs</a> 2068(default: nobody)</b></DT><DD> 2069 2070<p> 2071The default rights used by the <a href="local.8.html">local(8)</a> delivery agent for delivery 2072to external file or command. These rights are used when delivery 2073is requested from an <a href="aliases.5.html">aliases(5)</a> file that is owned by <b>root</b>, or 2074when delivery is done on behalf of <b>root</b>. <b>DO NOT SPECIFY A 2075PRIVILEGED USER OR THE POSTFIX OWNER</b>. 2076</p> 2077 2078 2079</DD> 2080 2081<DT><b><a name="default_process_limit">default_process_limit</a> 2082(default: 100)</b></DT><DD> 2083 2084<p> 2085The default maximal number of Postfix child processes that provide 2086a given service. This limit can be overruled for specific services 2087in the <a href="master.5.html">master.cf</a> file. 2088</p> 2089 2090 2091</DD> 2092 2093<DT><b><a name="default_rbl_reply">default_rbl_reply</a> 2094(default: see "postconf -d" output)</b></DT><DD> 2095 2096<p> 2097The default SMTP server response template for a request that is 2098rejected by an RBL-based restriction. This template can be overruled 2099by specific entries in the optional <a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> lookup table. 2100</p> 2101 2102<p> 2103This feature is available in Postfix 2.0 and later. 2104</p> 2105 2106<p> 2107The template is subject to exactly one level of $name substitution: 2108</p> 2109 2110<dl> 2111 2112<dt><b>$client</b></dt> 2113 2114<dd>The client hostname and IP address, formatted as name[address]. </dd> 2115 2116<dt><b>$client_address</b></dt> 2117 2118<dd>The client IP address. </dd> 2119 2120<dt><b>$client_name</b></dt> 2121 2122<dd>The client hostname or "unknown". See <a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> 2123for more details. </dd> 2124 2125<dt><b>$reverse_client_name</b></dt> 2126 2127<dd>The client hostname from address->name lookup, or "unknown". 2128See <a href="postconf.5.html#reject_unknown_reverse_client_hostname">reject_unknown_reverse_client_hostname</a> for more details. </dd> 2129 2130<dt><b>$helo_name</b></dt> 2131 2132<dd>The hostname given in HELO or EHLO command or empty string. </dd> 2133 2134<dt><b>$rbl_class</b></dt> 2135 2136<dd>The blacklisted entity type: Client host, Helo command, Sender 2137address, or Recipient address. </dd> 2138 2139<dt><b>$rbl_code</b></dt> 2140 2141<dd>The numerical SMTP response code, as specified with the 2142<a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> configuration parameter. Note: The numerical 2143SMTP response code is required, and must appear at the start of the 2144reply. With Postfix version 2.3 and later this information may be followed 2145by an <a href="http://tools.ietf.org/html/rfc3463">RFC 3463</a> enhanced status code. </dd> 2146 2147<dt><b>$rbl_domain</b></dt> 2148 2149<dd>The RBL domain where $rbl_what is blacklisted. </dd> 2150 2151<dt><b>$rbl_reason</b></dt> 2152 2153<dd>The reason why $rbl_what is blacklisted, or an empty string. </dd> 2154 2155<dt><b>$rbl_what</b></dt> 2156 2157<dd>The entity that is blacklisted (an IP address, a hostname, a domain 2158name, or an email address whose domain was blacklisted). </dd> 2159 2160<dt><b>$recipient</b></dt> 2161 2162<dd>The recipient address or <> in case of the null address. </dd> 2163 2164<dt><b>$recipient_domain</b></dt> 2165 2166<dd>The recipient domain or empty string. </dd> 2167 2168<dt><b>$recipient_name</b></dt> 2169 2170<dd>The recipient address localpart or <> in case of null address. </dd> 2171 2172<dt><b>$sender</b></dt> 2173 2174<dd>The sender address or <> in case of the null address. </dd> 2175 2176<dt><b>$sender_domain</b></dt> 2177 2178<dd>The sender domain or empty string. </dd> 2179 2180<dt><b>$sender_name</b></dt> 2181 2182<dd>The sender address localpart or <> in case of the null address. </dd> 2183 2184<dt><b>${name?text}</b></dt> 2185 2186<dd>Expands to `text' if $name is not empty. </dd> 2187 2188<dt><b>${name:text}</b></dt> 2189 2190<dd>Expands to `text' if $name is empty. </dd> 2191 2192</dl> 2193 2194<p> 2195Instead of $name you can also specify ${name} or $(name). 2196</p> 2197 2198<p> Note: when an enhanced status code is specified in an RBL reply 2199template, it is subject to modification. The following transformations 2200are needed when the same RBL reply template is used for client, 2201helo, sender, or recipient access restrictions. </p> 2202 2203<ul> 2204 2205<li> <p> When rejecting a sender address, the Postfix SMTP server 2206will transform a recipient DSN status (e.g., 4.1.1-4.1.6) into the 2207corresponding sender DSN status, and vice versa. </p> 2208 2209<li> <p> When rejecting non-address information (such as the HELO 2210command argument or the client hostname/address), the Postfix SMTP 2211server will transform a sender or recipient DSN status into a generic 2212non-address DSN status (e.g., 4.0.0). </p> 2213 2214</ul> 2215 2216 2217</DD> 2218 2219<DT><b><a name="default_recipient_limit">default_recipient_limit</a> 2220(default: 20000)</b></DT><DD> 2221 2222<p> 2223The default per-transport upper limit on the number of in-memory 2224recipients. These limits take priority over the global 2225<a href="postconf.5.html#qmgr_message_recipient_limit">qmgr_message_recipient_limit</a> after the message has been assigned 2226to the respective transports. See also <a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipient_limit</a> 2227and <a href="postconf.5.html#qmgr_message_recipient_minimum">qmgr_message_recipient_minimum</a>. 2228</p> 2229 2230<p> Use <a href="postconf.5.html#transport_recipient_limit"><i>transport</i>_recipient_limit</a> to specify a 2231transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2232name of the message delivery transport. 2233</p> 2234 2235 2236</DD> 2237 2238<DT><b><a name="default_recipient_refill_delay">default_recipient_refill_delay</a> 2239(default: 5s)</b></DT><DD> 2240 2241<p> 2242The default per-transport maximum delay between recipients refills. 2243When not all message recipients fit into the memory at once, keep loading 2244more of them at least once every this many seconds. This is used to 2245make sure the recipients are refilled in timely manner even when 2246$<a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a> is too high for too slow deliveries. 2247</p> 2248 2249<p> Use <a href="postconf.5.html#transport_recipient_refill_delay"><i>transport</i>_recipient_refill_delay</a> to specify a 2250transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2251name of the message delivery transport. 2252</p> 2253 2254<p> This feature is available in Postfix 2.4 and later. </p> 2255 2256 2257</DD> 2258 2259<DT><b><a name="default_recipient_refill_limit">default_recipient_refill_limit</a> 2260(default: 100)</b></DT><DD> 2261 2262<p> 2263The default per-transport limit on the number of recipients refilled at 2264once. When not all message recipients fit into the memory at once, keep 2265loading more of them in batches of at least this many at a time. See also 2266$<a href="postconf.5.html#default_recipient_refill_delay">default_recipient_refill_delay</a>, which may result in recipient batches 2267lower than this when this limit is too high for too slow deliveries. 2268</p> 2269 2270<p> Use <a href="postconf.5.html#transport_recipient_refill_limit"><i>transport</i>_recipient_refill_limit</a> to specify a 2271transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 2272name of the message delivery transport. 2273</p> 2274 2275<p> This feature is available in Postfix 2.4 and later. </p> 2276 2277 2278</DD> 2279 2280<DT><b><a name="default_transport">default_transport</a> 2281(default: smtp)</b></DT><DD> 2282 2283<p> 2284The default mail delivery transport and next-hop destination for 2285destinations that do not match $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>, 2286$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, 2287or $<a href="postconf.5.html#relay_domains">relay_domains</a>. This information can be overruled with the 2288<a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a> parameter and with the 2289<a href="transport.5.html">transport(5)</a> table. </p> 2290 2291<p> 2292In order of decreasing precedence, the nexthop destination is taken 2293from $<a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a>, $<a href="postconf.5.html#default_transport">default_transport</a>, 2294$<a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a>, $<a href="postconf.5.html#relayhost">relayhost</a>, or from the recipient 2295domain. 2296</p> 2297 2298<p> 2299Specify a string of the form <i>transport:nexthop</i>, where <i>transport</i> 2300is the name of a mail delivery transport defined in <a href="master.5.html">master.cf</a>. 2301The <i>:nexthop</i> destination is optional; its syntax is documented 2302in the manual page of the corresponding delivery agent. 2303</p> 2304 2305<p> 2306Example: 2307</p> 2308 2309<pre> 2310<a href="postconf.5.html#default_transport">default_transport</a> = uucp:relayhostname 2311</pre> 2312 2313 2314</DD> 2315 2316<DT><b><a name="default_verp_delimiters">default_verp_delimiters</a> 2317(default: +=)</b></DT><DD> 2318 2319<p> The two default VERP delimiter characters. These are used when 2320no explicit delimiters are specified with the SMTP XVERP command 2321or with the "<b>sendmail -V</b>" command-line option. Specify 2322characters that are allowed by the <a href="postconf.5.html#verp_delimiter_filter">verp_delimiter_filter</a> setting. 2323</p> 2324 2325<p> 2326This feature is available in Postfix 1.1 and later. 2327</p> 2328 2329 2330</DD> 2331 2332<DT><b><a name="defer_code">defer_code</a> 2333(default: 450)</b></DT><DD> 2334 2335<p> 2336The numerical Postfix SMTP server response code when a remote SMTP 2337client request is rejected by the "defer" restriction. 2338</p> 2339 2340<p> 2341Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 2342</p> 2343 2344 2345</DD> 2346 2347<DT><b><a name="defer_service_name">defer_service_name</a> 2348(default: defer)</b></DT><DD> 2349 2350<p> 2351The name of the defer service. This service is implemented by the 2352<a href="bounce.8.html">bounce(8)</a> daemon and maintains a record 2353of failed delivery attempts and generates non-delivery notifications. 2354</p> 2355 2356<p> 2357This feature is available in Postfix 2.0 and later. 2358</p> 2359 2360 2361</DD> 2362 2363<DT><b><a name="defer_transports">defer_transports</a> 2364(default: empty)</b></DT><DD> 2365 2366<p> 2367The names of message delivery transports that should not deliver mail 2368unless someone issues "<b>sendmail -q</b>" or equivalent. Specify zero 2369or more names of mail delivery transports names that appear in the 2370first field of <a href="master.5.html">master.cf</a>. 2371</p> 2372 2373<p> 2374Example: 2375</p> 2376 2377<pre> 2378<a href="postconf.5.html#defer_transports">defer_transports</a> = smtp 2379</pre> 2380 2381 2382</DD> 2383 2384<DT><b><a name="delay_logging_resolution_limit">delay_logging_resolution_limit</a> 2385(default: 2)</b></DT><DD> 2386 2387<p> The maximal number of digits after the decimal point when logging 2388sub-second delay values. Specify a number in the range 0..6. </p> 2389 2390<p> Large delay values are rounded off to an integral number seconds; 2391delay values below the <a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> are logged 2392as "0", and small delay values are logged with at most two-digit 2393precision. </p> 2394 2395<p> The format of the "delays=a/b/c/d" logging is as follows: </p> 2396 2397<ul> 2398 2399<li> a = time from message arrival to last <a href="QSHAPE_README.html#active_queue">active queue</a> entry 2400 2401<li> b = time from last <a href="QSHAPE_README.html#active_queue">active queue</a> entry to connection setup 2402 2403<li> c = time in connection setup, including DNS, EHLO and STARTTLS 2404 2405<li> d = time in message transmission 2406 2407</ul> 2408 2409<p> This feature is available in Postfix 2.3 and later. </p> 2410 2411 2412</DD> 2413 2414<DT><b><a name="delay_notice_recipient">delay_notice_recipient</a> 2415(default: postmaster)</b></DT><DD> 2416 2417<p> 2418The recipient of postmaster notifications with the message headers 2419of mail that cannot be delivered within $<a href="postconf.5.html#delay_warning_time">delay_warning_time</a> time 2420units. </p> 2421 2422<p> 2423This feature is enabled with the <a href="postconf.5.html#delay_warning_time">delay_warning_time</a> parameter. 2424</p> 2425 2426 2427</DD> 2428 2429<DT><b><a name="delay_warning_time">delay_warning_time</a> 2430(default: 0h)</b></DT><DD> 2431 2432<p> 2433The time after which the sender receives the message headers of 2434mail that is still queued. 2435</p> 2436 2437<p> 2438To enable this feature, specify a non-zero time value (an integral 2439value plus an optional one-letter suffix that specifies the time 2440unit). 2441</p> 2442 2443<p> 2444Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 2445The default time unit is h (hours). 2446</p> 2447 2448 2449</DD> 2450 2451<DT><b><a name="deliver_lock_attempts">deliver_lock_attempts</a> 2452(default: 20)</b></DT><DD> 2453 2454<p> 2455The maximal number of attempts to acquire an exclusive lock on a 2456mailbox file or <a href="bounce.8.html">bounce(8)</a> logfile. 2457</p> 2458 2459 2460</DD> 2461 2462<DT><b><a name="deliver_lock_delay">deliver_lock_delay</a> 2463(default: 1s)</b></DT><DD> 2464 2465<p> 2466The time between attempts to acquire an exclusive lock on a mailbox 2467file or <a href="bounce.8.html">bounce(8)</a> logfile. 2468</p> 2469 2470<p> 2471Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 2472The default time unit is s (seconds). 2473</p> 2474 2475 2476</DD> 2477 2478<DT><b><a name="destination_concurrency_feedback_debug">destination_concurrency_feedback_debug</a> 2479(default: no)</b></DT><DD> 2480 2481<p> Make the queue manager's feedback algorithm verbose for performance 2482analysis purposes. </p> 2483 2484<p> This feature is available in Postfix 2.5 and later. </p> 2485 2486 2487</DD> 2488 2489<DT><b><a name="detect_8bit_encoding_header">detect_8bit_encoding_header</a> 2490(default: yes)</b></DT><DD> 2491 2492<p> Automatically detect 8BITMIME body content by looking at 2493Content-Transfer-Encoding: message headers; historically, this 2494behavior was hard-coded to be "always on". </p> 2495 2496<p> This feature is available in Postfix 2.5 and later. </p> 2497 2498 2499</DD> 2500 2501<DT><b><a name="disable_dns_lookups">disable_dns_lookups</a> 2502(default: no)</b></DT><DD> 2503 2504<p> 2505Disable DNS lookups in the Postfix SMTP and LMTP clients. When 2506disabled, hosts are looked up with the getaddrinfo() system 2507library routine which normally also looks in /etc/hosts. 2508</p> 2509 2510<p> 2511DNS lookups are enabled by default. 2512</p> 2513 2514 2515</DD> 2516 2517<DT><b><a name="disable_mime_input_processing">disable_mime_input_processing</a> 2518(default: no)</b></DT><DD> 2519 2520<p> 2521Turn off MIME processing while receiving mail. This means that no 2522special treatment is given to Content-Type: message headers, and 2523that all text after the initial message headers is considered to 2524be part of the message body. 2525</p> 2526 2527<p> 2528This feature is available in Postfix 2.0 and later. 2529</p> 2530 2531<p> 2532Mime input processing is enabled by default, and is needed in order 2533to recognize MIME headers in message content. 2534</p> 2535 2536 2537</DD> 2538 2539<DT><b><a name="disable_mime_output_conversion">disable_mime_output_conversion</a> 2540(default: no)</b></DT><DD> 2541 2542<p> 2543Disable the conversion of 8BITMIME format to 7BIT format. Mime 2544output conversion is needed when the destination does not advertise 25458BITMIME support. 2546</p> 2547 2548<p> 2549This feature is available in Postfix 2.0 and later. 2550</p> 2551 2552 2553</DD> 2554 2555<DT><b><a name="disable_verp_bounces">disable_verp_bounces</a> 2556(default: no)</b></DT><DD> 2557 2558<p> 2559Disable sending one bounce report per recipient. 2560</p> 2561 2562<p> 2563The default, one per recipient, is what ezmlm needs. 2564</p> 2565 2566<p> 2567This feature is available in Postfix 1.1 and later. 2568</p> 2569 2570 2571</DD> 2572 2573<DT><b><a name="disable_vrfy_command">disable_vrfy_command</a> 2574(default: no)</b></DT><DD> 2575 2576<p> 2577Disable the SMTP VRFY command. This stops some techniques used to 2578harvest email addresses. 2579</p> 2580 2581<p> 2582Example: 2583</p> 2584 2585<pre> 2586<a href="postconf.5.html#disable_vrfy_command">disable_vrfy_command</a> = no 2587</pre> 2588 2589 2590</DD> 2591 2592<DT><b><a name="dnsblog_reply_delay">dnsblog_reply_delay</a> 2593(default: 0s)</b></DT><DD> 2594 2595<p> A debugging aid to artifically delay DNS responses. </p> 2596 2597<p> This feature is available in Postfix 2.8. </p> 2598 2599 2600</DD> 2601 2602<DT><b><a name="dnsblog_service_name">dnsblog_service_name</a> 2603(default: dnsblog)</b></DT><DD> 2604 2605<p> The name of the <a href="dnsblog.8.html">dnsblog(8)</a> service entry in <a href="master.5.html">master.cf</a>. This 2606service performs DNS white/blacklist lookups. </p> 2607 2608<p> This feature is available in Postfix 2.8 and later. </p> 2609 2610 2611</DD> 2612 2613<DT><b><a name="dont_remove">dont_remove</a> 2614(default: 0)</b></DT><DD> 2615 2616<p> 2617Don't remove queue files and save them to the "saved" mail queue. 2618This is a debugging aid. To inspect the envelope information and 2619content of a Postfix queue file, use the <a href="postcat.1.html">postcat(1)</a> command. 2620</p> 2621 2622 2623</DD> 2624 2625<DT><b><a name="double_bounce_sender">double_bounce_sender</a> 2626(default: double-bounce)</b></DT><DD> 2627 2628<p> The sender address of postmaster notifications that are generated 2629by the mail system. All mail to this address is silently discarded, 2630in order to terminate mail bounce loops. </p> 2631 2632 2633</DD> 2634 2635<DT><b><a name="duplicate_filter_limit">duplicate_filter_limit</a> 2636(default: 1000)</b></DT><DD> 2637 2638<p> The maximal number of addresses remembered by the address 2639duplicate filter for <a href="aliases.5.html">aliases(5)</a> or <a href="virtual.5.html">virtual(5)</a> alias expansion, or 2640for <a href="showq.8.html">showq(8)</a> queue displays. </p> 2641 2642 2643</DD> 2644 2645<DT><b><a name="empty_address_default_transport_maps_lookup_key">empty_address_default_transport_maps_lookup_key</a> 2646(default: <>)</b></DT><DD> 2647 2648<p> The <a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a> search string that 2649will be used instead of the null sender address. </p> 2650 2651<p> This feature is available in Postfix 2.7 and later. </p> 2652 2653 2654</DD> 2655 2656<DT><b><a name="empty_address_recipient">empty_address_recipient</a> 2657(default: MAILER-DAEMON)</b></DT><DD> 2658 2659<p> 2660The recipient of mail addressed to the null address. Postfix does 2661not accept such addresses in SMTP commands, but they may still be 2662created locally as the result of configuration or software error. 2663</p> 2664 2665 2666</DD> 2667 2668<DT><b><a name="empty_address_relayhost_maps_lookup_key">empty_address_relayhost_maps_lookup_key</a> 2669(default: <>)</b></DT><DD> 2670 2671<p> The <a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> search string that will be 2672used instead of the null sender address. </p> 2673 2674<p> This feature is available in Postfix 2.5 and later. With 2675earlier versions, <a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> lookups were 2676skipped for the null sender address. </p> 2677 2678 2679</DD> 2680 2681<DT><b><a name="enable_errors_to">enable_errors_to</a> 2682(default: no)</b></DT><DD> 2683 2684<p> Report mail delivery errors to the address specified with the 2685non-standard Errors-To: message header, instead of the envelope 2686sender address (this feature is removed with Postfix version 2.2, is 2687turned off by default with Postfix version 2.1, and is always turned on 2688with older Postfix versions). </p> 2689 2690 2691</DD> 2692 2693<DT><b><a name="enable_original_recipient">enable_original_recipient</a> 2694(default: yes)</b></DT><DD> 2695 2696<p> Enable support for the X-Original-To message header. This header 2697is needed for multi-recipient mailboxes. </p> 2698 2699<p> When this parameter is set to yes, the <a href="cleanup.8.html">cleanup(8)</a> daemon performs 2700duplicate elimination on distinct pairs of (original recipient, 2701rewritten recipient), and generates non-empty original recipient 2702queue file records. </p> 2703 2704<p> When this parameter is set to no, the <a href="cleanup.8.html">cleanup(8)</a> daemon performs 2705duplicate elimination on the rewritten recipient address only, and 2706generates empty original recipient queue file records. </p> 2707 2708<p> This feature is available in Postfix 2.1 and later. With Postfix 2709version 2.0, support for the X-Original-To message header is always turned 2710on. Postfix versions before 2.0 have no support for the X-Original-To 2711message header. </p> 2712 2713 2714</DD> 2715 2716<DT><b><a name="error_notice_recipient">error_notice_recipient</a> 2717(default: postmaster)</b></DT><DD> 2718 2719<p> The recipient of postmaster notifications about mail delivery 2720problems that are caused by policy, resource, software or protocol 2721errors. These notifications are enabled with the <a href="postconf.5.html#notify_classes">notify_classes</a> 2722parameter. </p> 2723 2724 2725</DD> 2726 2727<DT><b><a name="error_service_name">error_service_name</a> 2728(default: error)</b></DT><DD> 2729 2730<p> 2731The name of the <a href="error.8.html">error(8)</a> pseudo delivery agent. This service always 2732returns mail as undeliverable. 2733</p> 2734 2735<p> 2736This feature is available in Postfix 2.0 and later. 2737</p> 2738 2739 2740</DD> 2741 2742<DT><b><a name="execution_directory_expansion_filter">execution_directory_expansion_filter</a> 2743(default: see "postconf -d" output)</b></DT><DD> 2744 2745<p> Restrict the characters that the <a href="local.8.html">local(8)</a> delivery agent allows 2746in $name expansions of $<a href="postconf.5.html#command_execution_directory">command_execution_directory</a>. Characters 2747outside the allowed set are replaced by underscores. </p> 2748 2749<p> This feature is available in Postfix 2.2 and later. </p> 2750 2751 2752</DD> 2753 2754<DT><b><a name="expand_owner_alias">expand_owner_alias</a> 2755(default: no)</b></DT><DD> 2756 2757<p> 2758When delivering to an alias "aliasname" that has an "owner-aliasname" 2759companion alias, set the envelope sender address to the expansion 2760of the "owner-aliasname" alias. Normally, Postfix sets the envelope 2761sender address to the name of the "owner-aliasname" alias. 2762</p> 2763 2764 2765</DD> 2766 2767<DT><b><a name="export_environment">export_environment</a> 2768(default: see "postconf -d" output)</b></DT><DD> 2769 2770<p> 2771The list of environment variables that a Postfix process will export 2772to non-Postfix processes. The TZ variable is needed for sane 2773time keeping on System-V-ish systems. 2774</p> 2775 2776<p> 2777Specify a list of names and/or name=value pairs, separated by 2778whitespace or comma. The name=value form is supported with 2779Postfix version 2.1 and later. 2780</p> 2781 2782<p> 2783Example: 2784</p> 2785 2786<pre> 2787<a href="postconf.5.html#export_environment">export_environment</a> = TZ PATH=/bin:/usr/bin 2788</pre> 2789 2790 2791</DD> 2792 2793<DT><b><a name="extract_recipient_limit">extract_recipient_limit</a> 2794(default: 10240)</b></DT><DD> 2795 2796<p> 2797The maximal number of recipient addresses that Postfix will extract 2798from message headers when mail is submitted with "<b>sendmail -t</b>". 2799</p> 2800 2801<p> 2802This feature was removed in Postfix version 2.1. 2803</p> 2804 2805 2806</DD> 2807 2808<DT><b><a name="fallback_relay">fallback_relay</a> 2809(default: empty)</b></DT><DD> 2810 2811<p> 2812Optional list of relay hosts for SMTP destinations that can't be 2813found or that are unreachable. With Postfix 2.3 this parameter 2814is renamed to <a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a>. </p> 2815 2816<p> 2817By default, mail is returned to the sender when a destination is 2818not found, and delivery is deferred when a destination is unreachable. 2819</p> 2820 2821<p> The fallback relays must be SMTP destinations. Specify a domain, 2822host, host:port, [host]:port, [address] or [address]:port; the form 2823[host] turns off MX lookups. If you specify multiple SMTP 2824destinations, Postfix will try them in the specified order. </p> 2825 2826<p> Note: before Postfix 2.2, do not use the <a href="postconf.5.html#fallback_relay">fallback_relay</a> feature 2827when relaying mail 2828for a backup or primary MX domain. Mail would loop between the 2829Postfix MX host and the <a href="postconf.5.html#fallback_relay">fallback_relay</a> host when the final destination 2830is unavailable. </p> 2831 2832<ul> 2833 2834<li> In <a href="postconf.5.html">main.cf</a> specify "<a href="postconf.5.html#relay_transport">relay_transport</a> = relay", 2835 2836<li> In <a href="master.5.html">master.cf</a> specify "-o <a href="postconf.5.html#fallback_relay">fallback_relay</a> =" (i.e., empty) at 2837the end of the <tt>relay</tt> entry. 2838 2839<li> In transport maps, specify "relay:<i>nexthop...</i>" 2840as the right-hand side for backup or primary MX domain entries. 2841 2842</ul> 2843 2844<p> Postfix version 2.2 and later will not use the <a href="postconf.5.html#fallback_relay">fallback_relay</a> feature 2845for destinations that it is MX host for. 2846</p> 2847 2848 2849</DD> 2850 2851<DT><b><a name="fallback_transport">fallback_transport</a> 2852(default: empty)</b></DT><DD> 2853 2854<p> 2855Optional message delivery transport that the <a href="local.8.html">local(8)</a> delivery 2856agent should use for names that are not found in the <a href="aliases.5.html">aliases(5)</a> 2857or UNIX password database. 2858</p> 2859 2860<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 2861is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 2862<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 2863<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 2864 2865 2866</DD> 2867 2868<DT><b><a name="fallback_transport_maps">fallback_transport_maps</a> 2869(default: empty)</b></DT><DD> 2870 2871<p> Optional lookup tables with per-recipient message delivery 2872transports for recipients that the <a href="local.8.html">local(8)</a> delivery agent could 2873not find in the <a href="aliases.5.html">aliases(5)</a> or UNIX password database. </p> 2874 2875<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 2876is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 2877<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 2878<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 2879 2880<p> For safety reasons, this feature does not allow $number 2881substitutions in regular expression maps. </p> 2882 2883<p> This feature is available in Postfix 2.3 and later. </p> 2884 2885 2886</DD> 2887 2888<DT><b><a name="fast_flush_domains">fast_flush_domains</a> 2889(default: $<a href="postconf.5.html#relay_domains">relay_domains</a>)</b></DT><DD> 2890 2891<p> 2892Optional list of destinations that are eligible for per-destination 2893logfiles with mail that is queued to those destinations. 2894</p> 2895 2896<p> 2897By default, Postfix maintains "fast flush" logfiles only for 2898destinations that the Postfix SMTP server is willing to relay to 2899(i.e. the default is: "<a href="postconf.5.html#fast_flush_domains">fast_flush_domains</a> = $<a href="postconf.5.html#relay_domains">relay_domains</a>"; see 2900the <a href="postconf.5.html#relay_domains">relay_domains</a> parameter in the <a href="postconf.5.html">postconf(5)</a> manual). 2901</p> 2902 2903<p> Specify a list of hosts or domains, "/file/name" patterns or 2904"<a href="DATABASE_README.html">type:table</a>" lookup tables, separated by commas and/or whitespace. 2905Continue long lines by starting the next line with whitespace. A 2906"/file/name" pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" 2907lookup table is matched when the domain or its parent domain appears 2908as lookup key. </p> 2909 2910<p> 2911Specify "<a href="postconf.5.html#fast_flush_domains">fast_flush_domains</a> =" (i.e., empty) to disable the feature 2912altogether. 2913</p> 2914 2915 2916</DD> 2917 2918<DT><b><a name="fast_flush_purge_time">fast_flush_purge_time</a> 2919(default: 7d)</b></DT><DD> 2920 2921<p> 2922The time after which an empty per-destination "fast flush" logfile 2923is deleted. 2924</p> 2925 2926<p> 2927You can specify the time as a number, or as a number followed by 2928a letter that indicates the time unit: s=seconds, m=minutes, h=hours, 2929d=days, w=weeks. The default time unit is days. 2930</p> 2931 2932 2933</DD> 2934 2935<DT><b><a name="fast_flush_refresh_time">fast_flush_refresh_time</a> 2936(default: 12h)</b></DT><DD> 2937 2938<p> 2939The time after which a non-empty but unread per-destination "fast 2940flush" logfile needs to be refreshed. The contents of a logfile 2941are refreshed by requesting delivery of all messages listed in the 2942logfile. 2943</p> 2944 2945<p> 2946You can specify the time as a number, or as a number followed by 2947a letter that indicates the time unit: s=seconds, m=minutes, h=hours, 2948d=days, w=weeks. The default time unit is hours. 2949</p> 2950 2951 2952</DD> 2953 2954<DT><b><a name="fault_injection_code">fault_injection_code</a> 2955(default: 0)</b></DT><DD> 2956 2957<p> 2958Force specific internal tests to fail, to test the handling of 2959errors that are difficult to reproduce otherwise. 2960</p> 2961 2962 2963</DD> 2964 2965<DT><b><a name="flush_service_name">flush_service_name</a> 2966(default: flush)</b></DT><DD> 2967 2968<p> 2969The name of the <a href="flush.8.html">flush(8)</a> service. This service maintains per-destination 2970logfiles with the queue file names of mail that is queued for those 2971destinations. 2972</p> 2973 2974<p> 2975This feature is available in Postfix 2.0 and later. 2976</p> 2977 2978 2979</DD> 2980 2981<DT><b><a name="fork_attempts">fork_attempts</a> 2982(default: 5)</b></DT><DD> 2983 2984<p> The maximal number of attempts to fork() a child process. </p> 2985 2986 2987</DD> 2988 2989<DT><b><a name="fork_delay">fork_delay</a> 2990(default: 1s)</b></DT><DD> 2991 2992<p> The delay between attempts to fork() a child process. </p> 2993 2994<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 2995(weeks). The default time unit is s (seconds). </p> 2996 2997 2998</DD> 2999 3000<DT><b><a name="forward_expansion_filter">forward_expansion_filter</a> 3001(default: see "postconf -d" output)</b></DT><DD> 3002 3003<p> 3004Restrict the characters that the <a href="local.8.html">local(8)</a> delivery agent allows in 3005$name expansions of $<a href="postconf.5.html#forward_path">forward_path</a>. Characters outside the 3006allowed set are replaced by underscores. 3007</p> 3008 3009 3010</DD> 3011 3012<DT><b><a name="forward_path">forward_path</a> 3013(default: see "postconf -d" output)</b></DT><DD> 3014 3015<p> The <a href="local.8.html">local(8)</a> delivery agent search list for finding a .forward 3016file with user-specified delivery methods. The first file that is 3017found is used. </p> 3018 3019<p> The following $name expansions are done on <a href="postconf.5.html#forward_path">forward_path</a> before 3020the search actually happens. The result of $name expansion is 3021filtered with the character set that is specified with the 3022<a href="postconf.5.html#forward_expansion_filter">forward_expansion_filter</a> parameter. </p> 3023 3024<dl> 3025 3026<dt><b>$user</b></dt> 3027 3028<dd>The recipient's username. </dd> 3029 3030<dt><b>$shell</b></dt> 3031 3032<dd>The recipient's login shell pathname. </dd> 3033 3034<dt><b>$home</b></dt> 3035 3036<dd>The recipient's home directory. </dd> 3037 3038<dt><b>$recipient</b></dt> 3039 3040<dd>The full recipient address. </dd> 3041 3042<dt><b>$extension</b></dt> 3043 3044<dd>The optional recipient address extension. </dd> 3045 3046<dt><b>$domain</b></dt> 3047 3048<dd>The recipient domain. </dd> 3049 3050<dt><b>$local</b></dt> 3051 3052<dd>The entire recipient localpart. </dd> 3053 3054<dt><b>$<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a></b></dt> 3055 3056<dd>The system-wide recipient address extension delimiter. </dd> 3057 3058<dt><b>${name?value}</b></dt> 3059 3060<dd>Expands to <i>value</i> when <i>$name</i> is non-empty. </dd> 3061 3062<dt><b>${name:value}</b></dt> 3063 3064<dd>Expands to <i>value</i> when <i>$name</i> is empty. </dd> 3065 3066</dl> 3067 3068<p> 3069Instead of $name you can also specify ${name} or $(name). 3070</p> 3071 3072<p> 3073Examples: 3074</p> 3075 3076<pre> 3077<a href="postconf.5.html#forward_path">forward_path</a> = /var/forward/$user 3078<a href="postconf.5.html#forward_path">forward_path</a> = 3079 /var/forward/$user/.forward$<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a>$extension, 3080 /var/forward/$user/.forward 3081</pre> 3082 3083 3084</DD> 3085 3086<DT><b><a name="frozen_delivered_to">frozen_delivered_to</a> 3087(default: yes)</b></DT><DD> 3088 3089<p> Update the <a href="local.8.html">local(8)</a> delivery agent's idea of the Delivered-To: 3090address (see <a href="postconf.5.html#prepend_delivered_header">prepend_delivered_header</a>) only once, at the start of 3091a delivery attempt; do not update the Delivered-To: address while 3092expanding aliases or .forward files. </p> 3093 3094<p> This feature is available in Postfix 2.3 and later. With older 3095Postfix releases, the behavior is as if this parameter is set to 3096"no". The old setting can be expensive with deeply nested aliases 3097or .forward files. When an alias or .forward file changes the 3098Delivered-To: address, it ties up one queue file and one cleanup 3099process instance while mail is being forwarded. </p> 3100 3101 3102</DD> 3103 3104<DT><b><a name="hash_queue_depth">hash_queue_depth</a> 3105(default: 1)</b></DT><DD> 3106 3107<p> 3108The number of subdirectory levels for queue directories listed with 3109the <a href="postconf.5.html#hash_queue_names">hash_queue_names</a> parameter. 3110</p> 3111 3112<p> 3113After changing the <a href="postconf.5.html#hash_queue_names">hash_queue_names</a> or <a href="postconf.5.html#hash_queue_depth">hash_queue_depth</a> parameter, 3114execute the command "<b>postfix reload</b>". 3115</p> 3116 3117 3118</DD> 3119 3120<DT><b><a name="hash_queue_names">hash_queue_names</a> 3121(default: deferred, defer)</b></DT><DD> 3122 3123<p> 3124The names of queue directories that are split across multiple 3125subdirectory levels. 3126</p> 3127 3128<p> Before Postfix version 2.2, the default list of hashed queues 3129was significantly larger. Claims about improvements in file system 3130technology suggest that hashing of the <a href="QSHAPE_README.html#incoming_queue">incoming</a> and <a href="QSHAPE_README.html#active_queue">active queues</a> 3131is no longer needed. Fewer hashed directories speed up the time 3132needed to restart Postfix. </p> 3133 3134<p> 3135After changing the <a href="postconf.5.html#hash_queue_names">hash_queue_names</a> or <a href="postconf.5.html#hash_queue_depth">hash_queue_depth</a> parameter, 3136execute the command "<b>postfix reload</b>". 3137</p> 3138 3139 3140</DD> 3141 3142<DT><b><a name="header_address_token_limit">header_address_token_limit</a> 3143(default: 10240)</b></DT><DD> 3144 3145<p> 3146The maximal number of address tokens are allowed in an address 3147message header. Information that exceeds the limit is discarded. 3148The limit is enforced by the <a href="cleanup.8.html">cleanup(8)</a> server. 3149</p> 3150 3151 3152</DD> 3153 3154<DT><b><a name="header_checks">header_checks</a> 3155(default: empty)</b></DT><DD> 3156 3157<p> 3158Optional lookup tables for content inspection of primary non-MIME 3159message headers, as specified in the <a href="header_checks.5.html">header_checks(5)</a> manual page. 3160</p> 3161 3162 3163</DD> 3164 3165<DT><b><a name="header_size_limit">header_size_limit</a> 3166(default: 102400)</b></DT><DD> 3167 3168<p> 3169The maximal amount of memory in bytes for storing a message header. 3170If a header is larger, the excess is discarded. The limit is 3171enforced by the <a href="cleanup.8.html">cleanup(8)</a> server. 3172</p> 3173 3174 3175</DD> 3176 3177<DT><b><a name="helpful_warnings">helpful_warnings</a> 3178(default: yes)</b></DT><DD> 3179 3180<p> 3181Log warnings about problematic configuration settings, and provide 3182helpful suggestions. 3183</p> 3184 3185<p> 3186This feature is available in Postfix 2.0 and later. 3187</p> 3188 3189 3190</DD> 3191 3192<DT><b><a name="home_mailbox">home_mailbox</a> 3193(default: empty)</b></DT><DD> 3194 3195<p> 3196Optional pathname of a mailbox file relative to a <a href="local.8.html">local(8)</a> user's 3197home directory. 3198</p> 3199 3200<p> 3201Specify a pathname ending in "/" for qmail-style delivery. 3202</p> 3203 3204<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 3205is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 3206<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 3207<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 3208 3209<p> 3210Examples: 3211</p> 3212 3213<pre> 3214<a href="postconf.5.html#home_mailbox">home_mailbox</a> = Mailbox 3215<a href="postconf.5.html#home_mailbox">home_mailbox</a> = Maildir/ 3216</pre> 3217 3218 3219</DD> 3220 3221<DT><b><a name="hopcount_limit">hopcount_limit</a> 3222(default: 50)</b></DT><DD> 3223 3224<p> 3225The maximal number of Received: message headers that is allowed 3226in the primary message headers. A message that exceeds the limit 3227is bounced, in order to stop a mailer loop. 3228</p> 3229 3230 3231</DD> 3232 3233<DT><b><a name="html_directory">html_directory</a> 3234(default: see "postconf -d" output)</b></DT><DD> 3235 3236<p> 3237The location of Postfix HTML files that describe how to build, 3238configure or operate a specific Postfix subsystem or feature. 3239</p> 3240 3241 3242</DD> 3243 3244<DT><b><a name="ignore_mx_lookup_error">ignore_mx_lookup_error</a> 3245(default: no)</b></DT><DD> 3246 3247<p> Ignore DNS MX lookups that produce no response. By default, 3248the Postfix SMTP client defers delivery and tries again after some 3249delay. This behavior is required by the SMTP standard. </p> 3250 3251<p> 3252Specify "<a href="postconf.5.html#ignore_mx_lookup_error">ignore_mx_lookup_error</a> = yes" to force a DNS A record 3253lookup instead. This violates the SMTP standard and can result in 3254mis-delivery of mail. 3255</p> 3256 3257 3258</DD> 3259 3260<DT><b><a name="import_environment">import_environment</a> 3261(default: see "postconf -d" output)</b></DT><DD> 3262 3263<p> 3264The list of environment parameters that a Postfix process will 3265import from a non-Postfix parent process. Examples of relevant 3266parameters: 3267</p> 3268 3269<dl> 3270 3271<dt><b>TZ</b></dt> 3272 3273<dd>Needed for sane time keeping on most System-V-ish systems. </dd> 3274 3275<dt><b>DISPLAY</b></dt> 3276 3277<dd>Needed for debugging Postfix daemons with an X-windows debugger. </dd> 3278 3279<dt><b>XAUTHORITY</b></dt> 3280 3281<dd>Needed for debugging Postfix daemons with an X-windows debugger. </dd> 3282 3283<dt><b>MAIL_CONFIG</b></dt> 3284 3285<dd>Needed to make "<b>postfix -c</b>" work. </dd> 3286 3287</dl> 3288 3289<p> Specify a list of names and/or name=value pairs, separated by 3290whitespace or comma. The name=value form is supported with 3291Postfix version 2.1 and later. </p> 3292 3293 3294</DD> 3295 3296<DT><b><a name="in_flow_delay">in_flow_delay</a> 3297(default: 1s)</b></DT><DD> 3298 3299<p> Time to pause before accepting a new message, when the message 3300arrival rate exceeds the message delivery rate. This feature is 3301turned on by default (it's disabled on SCO UNIX due to an SCO bug). 3302</p> 3303 3304<p> 3305With the default 100 SMTP server process limit, "<a href="postconf.5.html#in_flow_delay">in_flow_delay</a> 3306= 1s" limits the mail inflow to 100 messages per second above the 3307number of messages delivered per second. 3308</p> 3309 3310<p> 3311Specify 0 to disable the feature. Valid delays are 0..10. 3312</p> 3313 3314 3315</DD> 3316 3317<DT><b><a name="inet_interfaces">inet_interfaces</a> 3318(default: all)</b></DT><DD> 3319 3320<p> The network interface addresses that this mail system receives 3321mail on. Specify "all" to receive mail on all network 3322interfaces (default), and "loopback-only" to receive mail 3323on loopback network interfaces only (Postfix version 2.2 and later). The 3324parameter also controls delivery of mail to <tt>user@[ip.address]</tt>. 3325</p> 3326 3327<p> 3328Note 1: you need to stop and start Postfix when this parameter changes. 3329</p> 3330 3331<p> Note 2: address information may be enclosed inside <tt>[]</tt>, 3332but this form is not required here. </p> 3333 3334<p> When <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> specifies just one IPv4 and/or IPv6 address 3335that is not a loopback address, the Postfix SMTP client will use 3336this address as the IP source address for outbound mail. Support 3337for IPv6 is available in Postfix version 2.2 and later. </p> 3338 3339<p> 3340On a multi-homed firewall with separate Postfix instances listening on the 3341"inside" and "outside" interfaces, this can prevent each instance from 3342being able to reach servers on the "other side" of the firewall. Setting 3343<a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> to 0.0.0.0 avoids the potential problem for 3344IPv4, and setting <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> to :: solves the problem 3345for IPv6. </p> 3346 3347<p> 3348A better solution for multi-homed firewalls is to leave <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 3349at the default value and instead use explicit IP addresses in 3350the <a href="master.5.html">master.cf</a> SMTP server definitions. This preserves the Postfix 3351SMTP client's 3352loop detection, by ensuring that each side of the firewall knows that the 3353other IP address is still the same host. Setting $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> to a 3354single IPv4 and/or IPV6 address is primarily useful with virtual 3355hosting of domains on 3356secondary IP addresses, when each IP address serves a different domain 3357(and has a different $<a href="postconf.5.html#myhostname">myhostname</a> setting). </p> 3358 3359<p> 3360See also the <a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> parameter, for network addresses that 3361are forwarded to Postfix by way of a proxy or address translator. 3362</p> 3363 3364<p> 3365Examples: 3366</p> 3367 3368<pre> 3369<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = all (DEFAULT) 3370<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = loopback-only (Postfix version 2.2 and later) 3371<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = 127.0.0.1 3372<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = 127.0.0.1, [::1] (Postfix version 2.2 and later) 3373<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> = 192.168.1.2, 127.0.0.1 3374</pre> 3375 3376 3377</DD> 3378 3379<DT><b><a name="inet_protocols">inet_protocols</a> 3380(default: ipv4)</b></DT><DD> 3381 3382<p> The Internet protocols Postfix will attempt to use when making 3383or accepting connections. Specify one or more of "ipv4" 3384or "ipv6", separated by whitespace or commas. The form 3385"all" is equivalent to "ipv4, ipv6" or "ipv4", depending 3386on whether the operating system implements IPv6. </p> 3387 3388<p> This feature is available in Postfix 2.2 and later. </p> 3389 3390<p> Note: you MUST stop and start Postfix after changing this 3391parameter. </p> 3392 3393<p> On systems that pre-date IPV6_V6ONLY support (<a href="http://tools.ietf.org/html/rfc3493">RFC 3493</a>), an 3394IPv6 server will also accept IPv4 connections, even when IPv4 is 3395turned off with the <a href="postconf.5.html#inet_protocols">inet_protocols</a> parameter. On systems with 3396IPV6_V6ONLY support, Postfix will use separate server sockets for 3397IPv6 and IPv4, and each will accept only connections for the 3398corresponding protocol. </p> 3399 3400<p> When IPv4 support is enabled via the <a href="postconf.5.html#inet_protocols">inet_protocols</a> parameter, 3401Postfix will to DNS type A record lookups, and will convert 3402IPv4-in-IPv6 client IP addresses (::ffff:1.2.3.4) to their original 3403IPv4 form (1.2.3.4). The latter is needed on hosts that pre-date 3404IPV6_V6ONLY support (<a href="http://tools.ietf.org/html/rfc3493">RFC 3493</a>). </p> 3405 3406<p> When IPv6 support is enabled via the <a href="postconf.5.html#inet_protocols">inet_protocols</a> parameter, 3407Postfix will do DNS type AAAA record lookups. </p> 3408 3409<p> When both IPv4 and IPv6 support are enabled, the Postfix SMTP 3410client will attempt to connect via IPv6 before attempting to use 3411IPv4. </p> 3412 3413<p> 3414Examples: 3415</p> 3416 3417<pre> 3418<a href="postconf.5.html#inet_protocols">inet_protocols</a> = ipv4 (DEFAULT) 3419<a href="postconf.5.html#inet_protocols">inet_protocols</a> = all 3420<a href="postconf.5.html#inet_protocols">inet_protocols</a> = ipv6 3421<a href="postconf.5.html#inet_protocols">inet_protocols</a> = ipv4, ipv6 3422</pre> 3423 3424 3425</DD> 3426 3427<DT><b><a name="initial_destination_concurrency">initial_destination_concurrency</a> 3428(default: 5)</b></DT><DD> 3429 3430<p> 3431The initial per-destination concurrency level for parallel delivery 3432to the same destination. 3433With per-destination recipient limit > 1, a destination is a domain, 3434otherwise it is a recipient. 3435</p> 3436 3437<p> Use <a href="postconf.5.html#transport_initial_destination_concurrency"><i>transport</i>_initial_destination_concurrency</a> to specify 3438a transport-specific override, where <i>transport</i> is the <a href="master.5.html">master.cf</a> 3439name of the message delivery transport (Postfix 2.5 and later). </p> 3440 3441<p> 3442Warning: with concurrency of 1, one bad message can be enough to 3443block all mail to a site. 3444</p> 3445 3446 3447</DD> 3448 3449<DT><b><a name="internal_mail_filter_classes">internal_mail_filter_classes</a> 3450(default: empty)</b></DT><DD> 3451 3452<p> What categories of Postfix-generated mail are subject to 3453before-queue content inspection by <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>, <a href="postconf.5.html#header_checks">header_checks</a> 3454and <a href="postconf.5.html#body_checks">body_checks</a>. Specify zero or more of the following, separated 3455by whitespace or comma. </p> 3456 3457<dl> 3458 3459<dt><b>bounce</b></dt> <dd> Inspect the content of delivery 3460status notifications. </dd> 3461 3462<dt><b>notify</b></dt> <dd> Inspect the content of postmaster 3463notifications by the <a href="smtp.8.html">smtp(8)</a> and <a href="smtpd.8.html">smtpd(8)</a> processes. </dd> 3464 3465</dl> 3466 3467<p> NOTE: It's generally not safe to enable content inspection of 3468Postfix-generated email messages. The user is warned. </p> 3469 3470<p> This feature is available in Postfix 2.3 and later. </p> 3471 3472 3473</DD> 3474 3475<DT><b><a name="invalid_hostname_reject_code">invalid_hostname_reject_code</a> 3476(default: 501)</b></DT><DD> 3477 3478<p> 3479The numerical Postfix SMTP server response code when the client 3480HELO or EHLO command parameter is rejected by the <a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> 3481restriction. 3482</p> 3483 3484<p> 3485Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 3486</p> 3487 3488 3489</DD> 3490 3491<DT><b><a name="ipc_idle">ipc_idle</a> 3492(default: version dependent)</b></DT><DD> 3493 3494<p> 3495The time after which a client closes an idle internal communication 3496channel. The purpose is to allow servers to terminate voluntarily 3497after they become idle. This is used, for example, by the address 3498resolving and rewriting clients. 3499</p> 3500 3501<p> With Postfix 2.4 the default value was reduced from 100s to 5s. </p> 3502 3503<p> 3504Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3505The default time unit is s (seconds). 3506</p> 3507 3508 3509</DD> 3510 3511<DT><b><a name="ipc_timeout">ipc_timeout</a> 3512(default: 3600s)</b></DT><DD> 3513 3514<p> 3515The time limit for sending or receiving information over an internal 3516communication channel. The purpose is to break out of deadlock 3517situations. If the time limit is exceeded the software aborts with a 3518fatal error. 3519</p> 3520 3521<p> 3522Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3523The default time unit is s (seconds). 3524</p> 3525 3526 3527</DD> 3528 3529<DT><b><a name="ipc_ttl">ipc_ttl</a> 3530(default: 1000s)</b></DT><DD> 3531 3532<p> 3533The time after which a client closes an active internal communication 3534channel. The purpose is to allow servers to terminate voluntarily 3535after reaching their client limit. This is used, for example, by 3536the address resolving and rewriting clients. 3537</p> 3538 3539<p> 3540Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3541The default time unit is s (seconds). 3542</p> 3543 3544<p> 3545This feature is available in Postfix 2.1 and later. 3546</p> 3547 3548 3549</DD> 3550 3551<DT><b><a name="line_length_limit">line_length_limit</a> 3552(default: 2048)</b></DT><DD> 3553 3554<p> Upon input, long lines are chopped up into pieces of at most 3555this length; upon delivery, long lines are reconstructed. </p> 3556 3557 3558</DD> 3559 3560<DT><b><a name="lmtp_address_preference">lmtp_address_preference</a> 3561(default: ipv6)</b></DT><DD> 3562 3563<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> 3564configuration parameter. See there for details. </p> 3565 3566<p> This feature is available in Postfix 2.8 and later. </p> 3567 3568 3569</DD> 3570 3571<DT><b><a name="lmtp_assume_final">lmtp_assume_final</a> 3572(default: no)</b></DT><DD> 3573 3574<p> When an LMTP server announces no DSN support, assume that the 3575server performs final delivery, and send "delivered" delivery status 3576notifications instead of "relayed". The default setting is backwards 3577compatible to avoid the infinetisimal possibility of breaking 3578existing LMTP-based content filters. </p> 3579 3580 3581</DD> 3582 3583<DT><b><a name="lmtp_bind_address">lmtp_bind_address</a> 3584(default: empty)</b></DT><DD> 3585 3586<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> configuration 3587parameter. See there for details. </p> 3588 3589<p> This feature is available in Postfix 2.3 and later. </p> 3590 3591 3592</DD> 3593 3594<DT><b><a name="lmtp_bind_address6">lmtp_bind_address6</a> 3595(default: empty)</b></DT><DD> 3596 3597<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> configuration 3598parameter. See there for details. </p> 3599 3600<p> This feature is available in Postfix 2.3 and later. </p> 3601 3602 3603</DD> 3604 3605<DT><b><a name="lmtp_body_checks">lmtp_body_checks</a> 3606(default: empty)</b></DT><DD> 3607 3608<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_body_checks">smtp_body_checks</a> configuration 3609parameter. See there for details. </p> 3610 3611<p> This feature is available in Postfix 2.5 and later. </p> 3612 3613 3614</DD> 3615 3616<DT><b><a name="lmtp_cache_connection">lmtp_cache_connection</a> 3617(default: yes)</b></DT><DD> 3618 3619<p> 3620Keep Postfix LMTP client connections open for up to $<a href="postconf.5.html#max_idle">max_idle</a> 3621seconds. When the LMTP client receives a request for the same 3622connection the connection is reused. 3623</p> 3624 3625<p> This parameter is available in Postfix version 2.2 and earlier. 3626With Postfix version 2.3 and later, see <a href="postconf.5.html#lmtp_connection_cache_on_demand">lmtp_connection_cache_on_demand</a>, 3627<a href="postconf.5.html#lmtp_connection_cache_destinations">lmtp_connection_cache_destinations</a>, or <a href="postconf.5.html#lmtp_connection_reuse_time_limit">lmtp_connection_reuse_time_limit</a>. 3628</p> 3629 3630<p> 3631The effectiveness of cached connections will be determined by the 3632number of LMTP servers in use, and the concurrency limit specified 3633for the LMTP client. Cached connections are closed under any of 3634the following conditions: 3635</p> 3636 3637<ul> 3638 3639<li> The LMTP client idle time limit is reached. This limit is 3640specified with the Postfix <a href="postconf.5.html#max_idle">max_idle</a> configuration parameter. 3641 3642<li> A delivery request specifies a different destination than the 3643one currently cached. 3644 3645<li> The per-process limit on the number of delivery requests is 3646reached. This limit is specified with the Postfix <a href="postconf.5.html#max_use">max_use</a> 3647configuration parameter. 3648 3649<li> Upon the onset of another delivery request, the LMTP server 3650associated with the current session does not respond to the RSET 3651command. 3652 3653</ul> 3654 3655<p> 3656Most of these limitations will be removed after Postfix implements 3657a connection cache that is shared among multiple LMTP client 3658programs. 3659</p> 3660 3661 3662</DD> 3663 3664<DT><b><a name="lmtp_cname_overrides_servername">lmtp_cname_overrides_servername</a> 3665(default: yes)</b></DT><DD> 3666 3667<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_cname_overrides_servername">smtp_cname_overrides_servername</a> 3668configuration parameter. See there for details. </p> 3669 3670<p> This feature is available in Postfix 2.3 and later. </p> 3671 3672 3673</DD> 3674 3675<DT><b><a name="lmtp_connect_timeout">lmtp_connect_timeout</a> 3676(default: 0s)</b></DT><DD> 3677 3678<p> The LMTP client time limit for completing a TCP connection, or 3679zero (use the operating system built-in time limit). When no 3680connection can be made within the deadline, the LMTP client tries 3681the next address on the mail exchanger list. </p> 3682 3683<p> 3684Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3685The default time unit is s (seconds). 3686</p> 3687 3688<p> 3689Example: 3690</p> 3691 3692<pre> 3693<a href="postconf.5.html#lmtp_connect_timeout">lmtp_connect_timeout</a> = 30s 3694</pre> 3695 3696 3697</DD> 3698 3699<DT><b><a name="lmtp_connection_cache_destinations">lmtp_connection_cache_destinations</a> 3700(default: empty)</b></DT><DD> 3701 3702<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> 3703configuration parameter. See there for details. </p> 3704 3705<p> This feature is available in Postfix 2.3 and later. </p> 3706 3707 3708</DD> 3709 3710<DT><b><a name="lmtp_connection_cache_on_demand">lmtp_connection_cache_on_demand</a> 3711(default: yes)</b></DT><DD> 3712 3713<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> 3714configuration parameter. See there for details. </p> 3715 3716<p> This feature is available in Postfix 2.3 and later. </p> 3717 3718 3719</DD> 3720 3721<DT><b><a name="lmtp_connection_cache_time_limit">lmtp_connection_cache_time_limit</a> 3722(default: 2s)</b></DT><DD> 3723 3724<p> The LMTP-specific version of the 3725<a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> configuration parameter. 3726See there for details. </p> 3727 3728<p> This feature is available in Postfix 2.3 and later. </p> 3729 3730 3731</DD> 3732 3733<DT><b><a name="lmtp_connection_reuse_time_limit">lmtp_connection_reuse_time_limit</a> 3734(default: 300s)</b></DT><DD> 3735 3736<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> 3737configuration parameter. See there for details. </p> 3738 3739<p> This feature is available in Postfix 2.3 and later. </p> 3740 3741 3742</DD> 3743 3744<DT><b><a name="lmtp_data_done_timeout">lmtp_data_done_timeout</a> 3745(default: 600s)</b></DT><DD> 3746 3747<p> The LMTP client time limit for sending the LMTP ".", and for 3748receiving the server response. When no response is received within 3749the deadline, a warning is logged that the mail may be delivered 3750multiple times. </p> 3751 3752<p> 3753Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3754The default time unit is s (seconds). 3755</p> 3756 3757 3758</DD> 3759 3760<DT><b><a name="lmtp_data_init_timeout">lmtp_data_init_timeout</a> 3761(default: 120s)</b></DT><DD> 3762 3763<p> 3764The LMTP client time limit for sending the LMTP DATA command, and 3765for receiving the server response. 3766</p> 3767 3768<p> 3769Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3770The default time unit is s (seconds). 3771</p> 3772 3773 3774</DD> 3775 3776<DT><b><a name="lmtp_data_xfer_timeout">lmtp_data_xfer_timeout</a> 3777(default: 180s)</b></DT><DD> 3778 3779<p> 3780The LMTP client time limit for sending the LMTP message content. 3781When the connection stalls for more than $<a href="postconf.5.html#lmtp_data_xfer_timeout">lmtp_data_xfer_timeout</a> 3782the LMTP client terminates the transfer. 3783</p> 3784 3785<p> 3786Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3787The default time unit is s (seconds). 3788</p> 3789 3790 3791</DD> 3792 3793<DT><b><a name="lmtp_defer_if_no_mx_address_found">lmtp_defer_if_no_mx_address_found</a> 3794(default: no)</b></DT><DD> 3795 3796<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_defer_if_no_mx_address_found">smtp_defer_if_no_mx_address_found</a> 3797configuration parameter. See there for details. </p> 3798 3799<p> This feature is available in Postfix 2.3 and later. </p> 3800 3801 3802</DD> 3803 3804<DT><b><a name="lmtp_destination_concurrency_limit">lmtp_destination_concurrency_limit</a> 3805(default: $<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a>)</b></DT><DD> 3806 3807<p> The maximal number of parallel deliveries to the same destination 3808via the lmtp message delivery transport. This limit is enforced by 3809the queue manager. The message delivery transport name is the first 3810field in the entry in the <a href="master.5.html">master.cf</a> file. </p> 3811 3812 3813</DD> 3814 3815<DT><b><a name="lmtp_destination_recipient_limit">lmtp_destination_recipient_limit</a> 3816(default: $<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a>)</b></DT><DD> 3817 3818<p> The maximal number of recipients per message for the lmtp 3819message delivery transport. This limit is enforced by the queue 3820manager. The message delivery transport name is the first field in 3821the entry in the <a href="master.5.html">master.cf</a> file. </p> 3822 3823<p> Setting this parameter to a value of 1 changes the meaning of 3824<a href="postconf.5.html#lmtp_destination_concurrency_limit">lmtp_destination_concurrency_limit</a> from concurrency per domain into 3825concurrency per recipient. </p> 3826 3827 3828</DD> 3829 3830<DT><b><a name="lmtp_discard_lhlo_keyword_address_maps">lmtp_discard_lhlo_keyword_address_maps</a> 3831(default: empty)</b></DT><DD> 3832 3833<p> Lookup tables, indexed by the remote LMTP server address, with 3834case insensitive lists of LHLO keywords (pipelining, starttls, 3835auth, etc.) that the LMTP client will ignore in the LHLO response 3836from a remote LMTP server. See <a href="postconf.5.html#lmtp_discard_lhlo_keywords">lmtp_discard_lhlo_keywords</a> for 3837details. The table is not indexed by hostname for consistency with 3838<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_discard_ehlo_keyword_address_maps</a>. </p> 3839 3840<p> This feature is available in Postfix 2.3 and later. </p> 3841 3842 3843</DD> 3844 3845<DT><b><a name="lmtp_discard_lhlo_keywords">lmtp_discard_lhlo_keywords</a> 3846(default: empty)</b></DT><DD> 3847 3848<p> A case insensitive list of LHLO keywords (pipelining, starttls, 3849auth, etc.) that the LMTP client will ignore in the LHLO response 3850from a remote LMTP server. </p> 3851 3852<p> This feature is available in Postfix 2.3 and later. </p> 3853 3854<p> Notes: </p> 3855 3856<ul> 3857 3858<li> <p> Specify the <b>silent-discard</b> pseudo keyword to prevent 3859this action from being logged. </p> 3860 3861<li> <p> Use the <a href="postconf.5.html#lmtp_discard_lhlo_keyword_address_maps">lmtp_discard_lhlo_keyword_address_maps</a> feature to 3862discard LHLO keywords selectively. </p> 3863 3864</ul> 3865 3866 3867</DD> 3868 3869<DT><b><a name="lmtp_dns_resolver_options">lmtp_dns_resolver_options</a> 3870(default: empty)</b></DT><DD> 3871 3872<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_dns_resolver_options">smtp_dns_resolver_options</a> 3873configuration parameter. See there for details. </p> 3874 3875<p> This feature is available in Postfix 2.8 and later. </p> 3876 3877 3878</DD> 3879 3880<DT><b><a name="lmtp_enforce_tls">lmtp_enforce_tls</a> 3881(default: no)</b></DT><DD> 3882 3883<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> configuration 3884parameter. See there for details. </p> 3885 3886<p> This feature is available in Postfix 2.3 and later. </p> 3887 3888 3889</DD> 3890 3891<DT><b><a name="lmtp_generic_maps">lmtp_generic_maps</a> 3892(default: empty)</b></DT><DD> 3893 3894<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_generic_maps">smtp_generic_maps</a> configuration 3895parameter. See there for details. </p> 3896 3897<p> This feature is available in Postfix 2.3 and later. </p> 3898 3899 3900</DD> 3901 3902<DT><b><a name="lmtp_header_checks">lmtp_header_checks</a> 3903(default: empty)</b></DT><DD> 3904 3905<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_header_checks">smtp_header_checks</a> configuration 3906parameter. See there for details. </p> 3907 3908<p> This feature is available in Postfix 2.5 and later. </p> 3909 3910 3911</DD> 3912 3913<DT><b><a name="lmtp_host_lookup">lmtp_host_lookup</a> 3914(default: dns)</b></DT><DD> 3915 3916<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> configuration 3917parameter. See there for details. </p> 3918 3919<p> This feature is available in Postfix 2.3 and later. </p> 3920 3921 3922</DD> 3923 3924<DT><b><a name="lmtp_lhlo_name">lmtp_lhlo_name</a> 3925(default: $<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 3926 3927<p> 3928The hostname to send in the LMTP LHLO command. 3929</p> 3930 3931<p> 3932The default value is the machine hostname. Specify a hostname or 3933[ip.add.re.ss]. 3934</p> 3935 3936<p> 3937This information can be specified in the <a href="postconf.5.html">main.cf</a> file for all LMTP 3938clients, or it can be specified in the <a href="master.5.html">master.cf</a> file for a specific 3939client, for example: 3940</p> 3941 3942<blockquote> 3943<pre> 3944/etc/postfix/<a href="master.5.html">master.cf</a>: 3945 mylmtp ... lmtp -o <a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a>=foo.bar.com 3946</pre> 3947</blockquote> 3948 3949<p> 3950This feature is available in Postfix 2.3 and later. 3951</p> 3952 3953 3954</DD> 3955 3956<DT><b><a name="lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> 3957(default: 300s)</b></DT><DD> 3958 3959<p> The LMTP client time limit for sending the LHLO command, and 3960for receiving the initial server response. </p> 3961 3962<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 3963(weeks). The default time unit is s (seconds). </p> 3964 3965 3966</DD> 3967 3968<DT><b><a name="lmtp_line_length_limit">lmtp_line_length_limit</a> 3969(default: 990)</b></DT><DD> 3970 3971<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_line_length_limit">smtp_line_length_limit</a> 3972configuration parameter. See there for details. </p> 3973 3974<p> This feature is available in Postfix 2.3 and later. </p> 3975 3976 3977</DD> 3978 3979<DT><b><a name="lmtp_mail_timeout">lmtp_mail_timeout</a> 3980(default: 300s)</b></DT><DD> 3981 3982<p> 3983The LMTP client time limit for sending the MAIL FROM command, and 3984for receiving the server response. 3985</p> 3986 3987<p> 3988Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 3989The default time unit is s (seconds). 3990</p> 3991 3992 3993</DD> 3994 3995<DT><b><a name="lmtp_mime_header_checks">lmtp_mime_header_checks</a> 3996(default: empty)</b></DT><DD> 3997 3998<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_mime_header_checks">smtp_mime_header_checks</a> 3999configuration parameter. See there for details. </p> 4000 4001<p> This feature is available in Postfix 2.5 and later. </p> 4002 4003 4004</DD> 4005 4006<DT><b><a name="lmtp_mx_address_limit">lmtp_mx_address_limit</a> 4007(default: 5)</b></DT><DD> 4008 4009<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> configuration 4010parameter. See there for details. </p> 4011 4012<p> This feature is available in Postfix 2.3 and later. </p> 4013 4014 4015</DD> 4016 4017<DT><b><a name="lmtp_mx_session_limit">lmtp_mx_session_limit</a> 4018(default: 2)</b></DT><DD> 4019 4020<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> configuration 4021parameter. See there for details. </p> 4022 4023<p> This feature is available in Postfix 2.3 and later. </p> 4024 4025 4026</DD> 4027 4028<DT><b><a name="lmtp_nested_header_checks">lmtp_nested_header_checks</a> 4029(default: empty)</b></DT><DD> 4030 4031<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_nested_header_checks">smtp_nested_header_checks</a> 4032configuration parameter. See there for details. </p> 4033 4034<p> This feature is available in Postfix 2.5 and later. </p> 4035 4036 4037</DD> 4038 4039<DT><b><a name="lmtp_pix_workaround_delay_time">lmtp_pix_workaround_delay_time</a> 4040(default: 10s)</b></DT><DD> 4041 4042<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> 4043configuration parameter. See there for details. </p> 4044 4045<p> This feature is available in Postfix 2.3 and later. </p> 4046 4047 4048</DD> 4049 4050<DT><b><a name="lmtp_pix_workaround_maps">lmtp_pix_workaround_maps</a> 4051(default: empty)</b></DT><DD> 4052 4053<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> 4054configuration parameter. See there for details. </p> 4055 4056<p> This feature is available in Postfix 2.4 and later. </p> 4057 4058 4059</DD> 4060 4061<DT><b><a name="lmtp_pix_workaround_threshold_time">lmtp_pix_workaround_threshold_time</a> 4062(default: 500s)</b></DT><DD> 4063 4064<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> 4065configuration parameter. See there for details. </p> 4066 4067<p> This feature is available in Postfix 2.3 and later. </p> 4068 4069 4070</DD> 4071 4072<DT><b><a name="lmtp_pix_workarounds">lmtp_pix_workarounds</a> 4073(default: empty)</b></DT><DD> 4074 4075<p> The LMTP-specific version of the smtp_pix_workaround 4076configuration parameter. See there for details. </p> 4077 4078<p> This feature is available in Postfix 2.4 and later. </p> 4079 4080 4081</DD> 4082 4083<DT><b><a name="lmtp_quit_timeout">lmtp_quit_timeout</a> 4084(default: 300s)</b></DT><DD> 4085 4086<p> 4087The LMTP client time limit for sending the QUIT command, and for 4088receiving the server response. 4089</p> 4090 4091<p> 4092Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 4093The default time unit is s (seconds). 4094</p> 4095 4096 4097</DD> 4098 4099<DT><b><a name="lmtp_quote_rfc821_envelope">lmtp_quote_rfc821_envelope</a> 4100(default: yes)</b></DT><DD> 4101 4102<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a> 4103configuration parameter. See there for details. </p> 4104 4105<p> This feature is available in Postfix 2.3 and later. </p> 4106 4107 4108</DD> 4109 4110<DT><b><a name="lmtp_randomize_addresses">lmtp_randomize_addresses</a> 4111(default: yes)</b></DT><DD> 4112 4113<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> 4114configuration parameter. See there for details. </p> 4115 4116<p> This feature is available in Postfix 2.3 and later. </p> 4117 4118 4119</DD> 4120 4121<DT><b><a name="lmtp_rcpt_timeout">lmtp_rcpt_timeout</a> 4122(default: 300s)</b></DT><DD> 4123 4124<p> 4125The LMTP client time limit for sending the RCPT TO command, and 4126for receiving the server response. 4127</p> 4128 4129<p> 4130Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 4131The default time unit is s (seconds). 4132</p> 4133 4134 4135</DD> 4136 4137<DT><b><a name="lmtp_reply_filter">lmtp_reply_filter</a> 4138(default: empty)</b></DT><DD> 4139 4140<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_reply_filter">smtp_reply_filter</a> 4141configuration parameter. See there for details. </p> 4142 4143<p> This feature is available in Postfix 2.7 and later. </p> 4144 4145 4146</DD> 4147 4148<DT><b><a name="lmtp_rset_timeout">lmtp_rset_timeout</a> 4149(default: 20s)</b></DT><DD> 4150 4151<p> The LMTP client time limit for sending the RSET command, and 4152for receiving the server response. The LMTP client sends RSET in 4153order to finish a recipient address probe, or to verify that a 4154cached connection is still alive. </p> 4155 4156<p> 4157Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 4158The default time unit is s (seconds). 4159</p> 4160 4161 4162</DD> 4163 4164<DT><b><a name="lmtp_sasl_auth_cache_name">lmtp_sasl_auth_cache_name</a> 4165(default: empty)</b></DT><DD> 4166 4167<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> 4168configuration parameter. See there for details. </p> 4169 4170<p> This feature is available in Postfix 2.5 and later. </p> 4171 4172 4173</DD> 4174 4175<DT><b><a name="lmtp_sasl_auth_cache_time">lmtp_sasl_auth_cache_time</a> 4176(default: 90d)</b></DT><DD> 4177 4178<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a> 4179configuration parameter. See there for details. </p> 4180 4181<p> This feature is available in Postfix 2.5 and later. </p> 4182 4183 4184</DD> 4185 4186<DT><b><a name="lmtp_sasl_auth_enable">lmtp_sasl_auth_enable</a> 4187(default: no)</b></DT><DD> 4188 4189<p> 4190Enable SASL authentication in the Postfix LMTP client. 4191</p> 4192 4193 4194</DD> 4195 4196<DT><b><a name="lmtp_sasl_auth_soft_bounce">lmtp_sasl_auth_soft_bounce</a> 4197(default: yes)</b></DT><DD> 4198 4199<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> 4200configuration parameter. See there for details. </p> 4201 4202<p> This feature is available in Postfix 2.5 and later. </p> 4203 4204 4205</DD> 4206 4207<DT><b><a name="lmtp_sasl_mechanism_filter">lmtp_sasl_mechanism_filter</a> 4208(default: empty)</b></DT><DD> 4209 4210<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> 4211configuration parameter. See there for details. </p> 4212 4213<p> This feature is available in Postfix 2.3 and later. </p> 4214 4215 4216</DD> 4217 4218<DT><b><a name="lmtp_sasl_password_maps">lmtp_sasl_password_maps</a> 4219(default: empty)</b></DT><DD> 4220 4221<p> 4222Optional LMTP client lookup tables with one username:password entry 4223per host or domain. If a remote host or domain has no username:password 4224entry, then the Postfix LMTP client will not attempt to authenticate 4225to the remote host. 4226</p> 4227 4228 4229</DD> 4230 4231<DT><b><a name="lmtp_sasl_path">lmtp_sasl_path</a> 4232(default: empty)</b></DT><DD> 4233 4234<p> Implementation-specific information that is passed through to 4235the SASL plug-in implementation that is selected with 4236<b><a href="postconf.5.html#lmtp_sasl_type">lmtp_sasl_type</a></b>. Typically this specifies the name of a 4237configuration file or rendezvous point. </p> 4238 4239<p> This feature is available in Postfix 2.3 and later. </p> 4240 4241 4242</DD> 4243 4244<DT><b><a name="lmtp_sasl_security_options">lmtp_sasl_security_options</a> 4245(default: noplaintext, noanonymous)</b></DT><DD> 4246 4247<p> SASL security options; as of Postfix 2.3 the list of available 4248features depends on the SASL client implementation that is selected 4249with <b><a href="postconf.5.html#lmtp_sasl_type">lmtp_sasl_type</a></b>. </p> 4250 4251<p> The following security features are defined for the <b>cyrus</b> 4252client SASL implementation: </p> 4253 4254<dl> 4255 4256<dt><b>noplaintext</b></dt> 4257 4258<dd>Disallow authentication methods that use plaintext passwords. </dd> 4259 4260<dt><b>noactive</b></dt> 4261 4262<dd>Disallow authentication methods that are vulnerable to non-dictionary 4263active attacks. </dd> 4264 4265<dt><b>nodictionary</b></dt> 4266 4267<dd>Disallow authentication methods that are vulnerable to passive 4268dictionary attack. </dd> 4269 4270<dt><b>noanonymous</b></dt> 4271 4272<dd>Disallow anonymous logins. </dd> 4273 4274</dl> 4275 4276<p> 4277Example: 4278</p> 4279 4280<pre> 4281<a href="postconf.5.html#lmtp_sasl_security_options">lmtp_sasl_security_options</a> = noplaintext 4282</pre> 4283 4284 4285</DD> 4286 4287<DT><b><a name="lmtp_sasl_tls_security_options">lmtp_sasl_tls_security_options</a> 4288(default: $<a href="postconf.5.html#lmtp_sasl_security_options">lmtp_sasl_security_options</a>)</b></DT><DD> 4289 4290<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a> 4291configuration parameter. See there for details. </p> 4292 4293<p> This feature is available in Postfix 2.3 and later. </p> 4294 4295 4296</DD> 4297 4298<DT><b><a name="lmtp_sasl_tls_verified_security_options">lmtp_sasl_tls_verified_security_options</a> 4299(default: $<a href="postconf.5.html#lmtp_sasl_tls_security_options">lmtp_sasl_tls_security_options</a>)</b></DT><DD> 4300 4301<p> The LMTP-specific version of the 4302<a href="postconf.5.html#smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a> configuration parameter. 4303See there for details. </p> 4304 4305<p> This feature is available in Postfix 2.3 and later. </p> 4306 4307 4308</DD> 4309 4310<DT><b><a name="lmtp_sasl_type">lmtp_sasl_type</a> 4311(default: cyrus)</b></DT><DD> 4312 4313<p> The SASL plug-in type that the Postfix LMTP client should use 4314for authentication. The available types are listed with the 4315"<b>postconf -A</b>" command. </p> 4316 4317<p> This feature is available in Postfix 2.3 and later. </p> 4318 4319 4320</DD> 4321 4322<DT><b><a name="lmtp_send_xforward_command">lmtp_send_xforward_command</a> 4323(default: no)</b></DT><DD> 4324 4325<p> 4326Send an XFORWARD command to the LMTP server when the LMTP LHLO 4327server response announces XFORWARD support. This allows an <a href="lmtp.8.html">lmtp(8)</a> 4328delivery agent, used for content filter message injection, to 4329forward the name, address, protocol and HELO name of the original 4330client to the content filter and downstream queuing LMTP server. 4331Before you change the value to yes, it is best to make sure that 4332your content filter supports this command. 4333</p> 4334 4335<p> 4336This feature is available in Postfix 2.1 and later. 4337</p> 4338 4339 4340</DD> 4341 4342<DT><b><a name="lmtp_sender_dependent_authentication">lmtp_sender_dependent_authentication</a> 4343(default: no)</b></DT><DD> 4344 4345<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_sender_dependent_authentication">smtp_sender_dependent_authentication</a> 4346configuration parameter. See there for details. </p> 4347 4348<p> This feature is available in Postfix 2.3 and later. </p> 4349 4350 4351</DD> 4352 4353<DT><b><a name="lmtp_skip_5xx_greeting">lmtp_skip_5xx_greeting</a> 4354(default: yes)</b></DT><DD> 4355 4356<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> 4357configuration parameter. See there for details. </p> 4358 4359<p> This feature is available in Postfix 2.3 and later. </p> 4360 4361 4362</DD> 4363 4364<DT><b><a name="lmtp_skip_quit_response">lmtp_skip_quit_response</a> 4365(default: no)</b></DT><DD> 4366 4367<p> 4368Wait for the response to the LMTP QUIT command. 4369</p> 4370 4371 4372</DD> 4373 4374<DT><b><a name="lmtp_starttls_timeout">lmtp_starttls_timeout</a> 4375(default: 300s)</b></DT><DD> 4376 4377<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_starttls_timeout">smtp_starttls_timeout</a> configuration 4378parameter. See there for details. </p> 4379 4380<p> This feature is available in Postfix 2.3 and later. </p> 4381 4382 4383</DD> 4384 4385<DT><b><a name="lmtp_tcp_port">lmtp_tcp_port</a> 4386(default: 24)</b></DT><DD> 4387 4388<p> 4389The default TCP port that the Postfix LMTP client connects to. 4390</p> 4391 4392 4393</DD> 4394 4395<DT><b><a name="lmtp_tls_CAfile">lmtp_tls_CAfile</a> 4396(default: empty)</b></DT><DD> 4397 4398<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a> 4399configuration parameter. See there for details. </p> 4400 4401<p> This feature is available in Postfix 2.3 and later. </p> 4402 4403 4404</DD> 4405 4406<DT><b><a name="lmtp_tls_CApath">lmtp_tls_CApath</a> 4407(default: empty)</b></DT><DD> 4408 4409<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> 4410configuration parameter. See there for details. </p> 4411 4412<p> This feature is available in Postfix 2.3 and later. </p> 4413 4414 4415</DD> 4416 4417<DT><b><a name="lmtp_tls_block_early_mail_reply">lmtp_tls_block_early_mail_reply</a> 4418(default: empty)</b></DT><DD> 4419 4420<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> 4421configuration parameter. See there for details. </p> 4422 4423<p> This feature is available in Postfix 2.7 and later. </p> 4424 4425 4426</DD> 4427 4428<DT><b><a name="lmtp_tls_cert_file">lmtp_tls_cert_file</a> 4429(default: empty)</b></DT><DD> 4430 4431<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> 4432configuration parameter. See there for details. </p> 4433 4434<p> This feature is available in Postfix 2.3 and later. </p> 4435 4436 4437</DD> 4438 4439<DT><b><a name="lmtp_tls_ciphers">lmtp_tls_ciphers</a> 4440(default: export)</b></DT><DD> 4441 4442<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> configuration 4443parameter. See there for details. </p> 4444 4445<p> This feature is available in Postfix 2.6 and later. </p> 4446 4447 4448</DD> 4449 4450<DT><b><a name="lmtp_tls_dcert_file">lmtp_tls_dcert_file</a> 4451(default: empty)</b></DT><DD> 4452 4453<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> 4454configuration parameter. See there for details. </p> 4455 4456<p> This feature is available in Postfix 2.3 and later. </p> 4457 4458 4459</DD> 4460 4461<DT><b><a name="lmtp_tls_dkey_file">lmtp_tls_dkey_file</a> 4462(default: $<a href="postconf.5.html#lmtp_tls_dcert_file">lmtp_tls_dcert_file</a>)</b></DT><DD> 4463 4464<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_dkey_file">smtp_tls_dkey_file</a> 4465configuration parameter. See there for details. </p> 4466 4467<p> This feature is available in Postfix 2.3 and later. </p> 4468 4469 4470</DD> 4471 4472<DT><b><a name="lmtp_tls_eccert_file">lmtp_tls_eccert_file</a> 4473(default: empty)</b></DT><DD> 4474 4475<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> configuration 4476parameter. See there for details. </p> 4477 4478<p> This feature is available in Postfix 2.6 and later, when Postfix is 4479compiled and linked with OpenSSL 1.0.0 or later. </p> 4480 4481 4482</DD> 4483 4484<DT><b><a name="lmtp_tls_eckey_file">lmtp_tls_eckey_file</a> 4485(default: empty)</b></DT><DD> 4486 4487<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_eckey_file">smtp_tls_eckey_file</a> configuration 4488parameter. See there for details. </p> 4489 4490<p> This feature is available in Postfix 2.6 and later, when Postfix is 4491compiled and linked with OpenSSL 1.0.0 or later. </p> 4492 4493 4494</DD> 4495 4496<DT><b><a name="lmtp_tls_enforce_peername">lmtp_tls_enforce_peername</a> 4497(default: yes)</b></DT><DD> 4498 4499<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> 4500configuration parameter. See there for details. </p> 4501 4502<p> This feature is available in Postfix 2.3 and later. </p> 4503 4504 4505</DD> 4506 4507<DT><b><a name="lmtp_tls_exclude_ciphers">lmtp_tls_exclude_ciphers</a> 4508(default: empty)</b></DT><DD> 4509 4510<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> 4511configuration parameter. See there for details. </p> 4512 4513<p> This feature is available in Postfix 2.3 and later. </p> 4514 4515 4516</DD> 4517 4518<DT><b><a name="lmtp_tls_fingerprint_cert_match">lmtp_tls_fingerprint_cert_match</a> 4519(default: empty)</b></DT><DD> 4520 4521<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> 4522configuration parameter. See there for details. </p> 4523 4524<p> This feature is available in Postfix 2.5 and later. </p> 4525 4526 4527</DD> 4528 4529<DT><b><a name="lmtp_tls_fingerprint_digest">lmtp_tls_fingerprint_digest</a> 4530(default: md5)</b></DT><DD> 4531 4532<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> 4533configuration parameter. See there for details. </p> 4534 4535<p> This feature is available in Postfix 2.5 and later. </p> 4536 4537 4538</DD> 4539 4540<DT><b><a name="lmtp_tls_key_file">lmtp_tls_key_file</a> 4541(default: $<a href="postconf.5.html#lmtp_tls_cert_file">lmtp_tls_cert_file</a>)</b></DT><DD> 4542 4543<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_key_file">smtp_tls_key_file</a> 4544configuration parameter. See there for details. </p> 4545 4546<p> This feature is available in Postfix 2.3 and later. </p> 4547 4548 4549</DD> 4550 4551<DT><b><a name="lmtp_tls_loglevel">lmtp_tls_loglevel</a> 4552(default: 0)</b></DT><DD> 4553 4554<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> 4555configuration parameter. See there for details. </p> 4556 4557<p> This feature is available in Postfix 2.3 and later. </p> 4558 4559 4560</DD> 4561 4562<DT><b><a name="lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a> 4563(default: empty)</b></DT><DD> 4564 4565<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> 4566configuration parameter. See there for details. </p> 4567 4568<p> This feature is available in Postfix 2.3 and later. </p> 4569 4570 4571</DD> 4572 4573<DT><b><a name="lmtp_tls_mandatory_exclude_ciphers">lmtp_tls_mandatory_exclude_ciphers</a> 4574(default: empty)</b></DT><DD> 4575 4576<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> 4577configuration parameter. See there for details. </p> 4578 4579<p> This feature is available in Postfix 2.3 and later. </p> 4580 4581 4582</DD> 4583 4584<DT><b><a name="lmtp_tls_mandatory_protocols">lmtp_tls_mandatory_protocols</a> 4585(default: SSLv3, TLSv1)</b></DT><DD> 4586 4587<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> 4588configuration parameter. See there for details. </p> 4589 4590<p> This feature is available in Postfix 2.3 and later. </p> 4591 4592 4593</DD> 4594 4595<DT><b><a name="lmtp_tls_note_starttls_offer">lmtp_tls_note_starttls_offer</a> 4596(default: no)</b></DT><DD> 4597 4598<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_note_starttls_offer">smtp_tls_note_starttls_offer</a> 4599configuration parameter. See there for details. </p> 4600 4601<p> This feature is available in Postfix 2.3 and later. </p> 4602 4603 4604</DD> 4605 4606<DT><b><a name="lmtp_tls_per_site">lmtp_tls_per_site</a> 4607(default: empty)</b></DT><DD> 4608 4609<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> configuration 4610parameter. See there for details. </p> 4611 4612<p> This feature is available in Postfix 2.3 and later. </p> 4613 4614 4615</DD> 4616 4617<DT><b><a name="lmtp_tls_policy_maps">lmtp_tls_policy_maps</a> 4618(default: empty)</b></DT><DD> 4619 4620<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> 4621configuration parameter. See there for details. </p> 4622 4623<p> This feature is available in Postfix 2.3 and later. </p> 4624 4625 4626</DD> 4627 4628<DT><b><a name="lmtp_tls_protocols">lmtp_tls_protocols</a> 4629(default: empty)</b></DT><DD> 4630 4631<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> configuration 4632parameter. See there for details. </p> 4633 4634<p> This feature is available in Postfix 2.6 and later. </p> 4635 4636 4637</DD> 4638 4639<DT><b><a name="lmtp_tls_scert_verifydepth">lmtp_tls_scert_verifydepth</a> 4640(default: 9)</b></DT><DD> 4641 4642<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> 4643configuration parameter. See there for details. </p> 4644 4645<p> This feature is available in Postfix 2.3 and later. </p> 4646 4647 4648</DD> 4649 4650<DT><b><a name="lmtp_tls_secure_cert_match">lmtp_tls_secure_cert_match</a> 4651(default: nexthop)</b></DT><DD> 4652 4653<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> 4654configuration parameter. See there for details. </p> 4655 4656<p> This feature is available in Postfix 2.3 and later. </p> 4657 4658 4659</DD> 4660 4661<DT><b><a name="lmtp_tls_security_level">lmtp_tls_security_level</a> 4662(default: empty)</b></DT><DD> 4663 4664<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> configuration 4665parameter. See there for details. </p> 4666 4667<p> This feature is available in Postfix 2.3 and later. </p> 4668 4669 4670</DD> 4671 4672<DT><b><a name="lmtp_tls_session_cache_database">lmtp_tls_session_cache_database</a> 4673(default: empty)</b></DT><DD> 4674 4675<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> 4676configuration parameter. See there for details. </p> 4677 4678<p> This feature is available in Postfix 2.3 and later. </p> 4679 4680 4681</DD> 4682 4683<DT><b><a name="lmtp_tls_session_cache_timeout">lmtp_tls_session_cache_timeout</a> 4684(default: 3600s)</b></DT><DD> 4685 4686<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> 4687configuration parameter. See there for details. </p> 4688 4689<p> This feature is available in Postfix 2.3 and later. </p> 4690 4691 4692</DD> 4693 4694<DT><b><a name="lmtp_tls_verify_cert_match">lmtp_tls_verify_cert_match</a> 4695(default: hostname)</b></DT><DD> 4696 4697<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> 4698configuration parameter. See there for details. </p> 4699 4700<p> This feature is available in Postfix 2.3 and later. </p> 4701 4702 4703</DD> 4704 4705<DT><b><a name="lmtp_use_tls">lmtp_use_tls</a> 4706(default: no)</b></DT><DD> 4707 4708<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> configuration 4709parameter. See there for details. </p> 4710 4711<p> This feature is available in Postfix 2.3 and later. </p> 4712 4713 4714</DD> 4715 4716<DT><b><a name="lmtp_xforward_timeout">lmtp_xforward_timeout</a> 4717(default: 300s)</b></DT><DD> 4718 4719<p> 4720The LMTP client time limit for sending the XFORWARD command, and 4721for receiving the server response. 4722</p> 4723 4724<p> 4725In case of problems the client does NOT try the next address on 4726the mail exchanger list. 4727</p> 4728 4729<p> 4730Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 4731The default time unit is s (seconds). 4732</p> 4733 4734<p> 4735This feature is available in Postfix 2.1 and later. 4736</p> 4737 4738 4739</DD> 4740 4741<DT><b><a name="local_command_shell">local_command_shell</a> 4742(default: empty)</b></DT><DD> 4743 4744<p> 4745Optional shell program for <a href="local.8.html">local(8)</a> delivery to non-Postfix command. 4746By default, non-Postfix commands are executed directly; commands 4747are given to given to the default shell (typically, /bin/sh) only 4748when they contain shell meta characters or shell built-in commands. 4749</p> 4750 4751<p> "sendmail's restricted shell" (smrsh) is what most people will 4752use in order to restrict what programs can be run from e.g. .forward 4753files (smrsh is part of the Sendmail distribution). </p> 4754 4755<p> Note: when a shell program is specified, it is invoked even 4756when the command contains no shell built-in commands or meta 4757characters. </p> 4758 4759<p> 4760Example: 4761</p> 4762 4763<pre> 4764<a href="postconf.5.html#local_command_shell">local_command_shell</a> = /some/where/smrsh -c 4765<a href="postconf.5.html#local_command_shell">local_command_shell</a> = /bin/bash -c 4766</pre> 4767 4768 4769</DD> 4770 4771<DT><b><a name="local_destination_concurrency_limit">local_destination_concurrency_limit</a> 4772(default: 2)</b></DT><DD> 4773 4774<p> The maximal number of parallel deliveries via the local mail 4775delivery transport to the same recipient (when 4776"<a href="postconf.5.html#local_destination_recipient_limit">local_destination_recipient_limit</a> = 1") or the maximal number of 4777parallel deliveries to the same <a href="ADDRESS_CLASS_README.html#local_domain_class">local domain</a> (when 4778"<a href="postconf.5.html#local_destination_recipient_limit">local_destination_recipient_limit</a> > 1"). This limit is enforced by 4779the queue manager. The message delivery transport name is the first 4780field in the entry in the <a href="master.5.html">master.cf</a> file. </p> 4781 4782<p> A low limit of 2 is recommended, just in case someone has an 4783expensive shell command in a .forward file or in an alias (e.g., 4784a mailing list manager). You don't want to run lots of those at 4785the same time. </p> 4786 4787 4788</DD> 4789 4790<DT><b><a name="local_destination_recipient_limit">local_destination_recipient_limit</a> 4791(default: 1)</b></DT><DD> 4792 4793<p> The maximal number of recipients per message delivery via the 4794local mail delivery transport. This limit is enforced by the queue 4795manager. The message delivery transport name is the first field in 4796the entry in the <a href="master.5.html">master.cf</a> file. </p> 4797 4798<p> Setting this parameter to a value > 1 changes the meaning of 4799<a href="postconf.5.html#local_destination_concurrency_limit">local_destination_concurrency_limit</a> from concurrency per recipient 4800into concurrency per domain. </p> 4801 4802 4803</DD> 4804 4805<DT><b><a name="local_header_rewrite_clients">local_header_rewrite_clients</a> 4806(default: <a href="postconf.5.html#permit_inet_interfaces">permit_inet_interfaces</a>)</b></DT><DD> 4807 4808<p> Rewrite message header addresses in mail from these clients and 4809update incomplete addresses with the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or 4810$<a href="postconf.5.html#mydomain">mydomain</a>; either don't rewrite message headers from other clients 4811at all, or rewrite message headers and update incomplete addresses 4812with the domain specified in the <a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> 4813parameter. </p> 4814 4815<p> See the <a href="postconf.5.html#append_at_myorigin">append_at_myorigin</a> and <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a> parameters 4816for details of how domain names are appended to incomplete addresses. 4817</p> 4818 4819<p> Specify a list of zero or more of the following: </p> 4820 4821<dl> 4822 4823<dt><b><a href="postconf.5.html#permit_inet_interfaces">permit_inet_interfaces</a></b></dt> 4824 4825<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4826client IP address matches $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>. This is enabled by 4827default. </dd> 4828 4829<dt><b><a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a></b></dt> 4830 4831<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4832client IP address matches any network or network address listed in 4833$<a href="postconf.5.html#mynetworks">mynetworks</a>. This setting will not prevent remote mail header 4834address rewriting when mail from a remote client is forwarded by 4835a neighboring system. </dd> 4836 4837<dt><b><a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a> </b></dt> 4838 4839<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4840client is successfully authenticated via the <a href="http://tools.ietf.org/html/rfc4954">RFC 4954</a> (AUTH) 4841protocol. </dd> 4842 4843<dt><b><a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a> </b></dt> 4844 4845<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4846client TLS certificate fingerprint is listed in $<a href="postconf.5.html#relay_clientcerts">relay_clientcerts</a>. 4847The fingerprint digest algorithm is configurable via the 4848<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> parameter (hard-coded as md5 prior to 4849Postfix version 2.5). </dd> 4850 4851<dt><b><a href="postconf.5.html#permit_tls_all_clientcerts">permit_tls_all_clientcerts</a> </b></dt> 4852 4853<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4854client TLS certificate is successfully verified, regardless of 4855whether it is listed on the server, and regardless of the certifying 4856authority. </dd> 4857 4858<dt><b><a name="check_address_map">check_address_map</a> <i><a href="DATABASE_README.html">type:table</a></i> </b></dt> 4859 4860<dt><b><i><a href="DATABASE_README.html">type:table</a></i> </b></dt> 4861 4862<dd> Append the domain name in $<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> when the 4863client IP address matches the specified lookup table. 4864The lookup result is ignored, and no subnet lookup is done. This 4865is suitable for, e.g., pop-before-smtp lookup tables. </dd> 4866 4867</dl> 4868 4869<p> Examples: </p> 4870 4871<p> The Postfix < 2.2 backwards compatible setting: always rewrite 4872message headers, and always append my own domain to incomplete 4873header addresses. </p> 4874 4875<blockquote> 4876<pre> 4877<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all 4878</pre> 4879</blockquote> 4880 4881<p> The purist (and default) setting: rewrite headers only in mail 4882from Postfix sendmail and in SMTP mail from this machine. </p> 4883 4884<blockquote> 4885<pre> 4886<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = <a href="postconf.5.html#permit_inet_interfaces">permit_inet_interfaces</a> 4887</pre> 4888</blockquote> 4889 4890<p> The intermediate setting: rewrite header addresses and append 4891$<a href="postconf.5.html#myorigin">myorigin</a> or $<a href="postconf.5.html#mydomain">mydomain</a> information only with mail from Postfix 4892sendmail, from local clients, or from authorized SMTP clients. </p> 4893 4894<p> Note: this setting will not prevent remote mail header address 4895rewriting when mail from a remote client is forwarded by a neighboring 4896system. </p> 4897 4898<blockquote> 4899<pre> 4900<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, 4901 <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a> <a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a> 4902 <a href="postconf.5.html#check_address_map">check_address_map</a> hash:/etc/postfix/pop-before-smtp 4903</pre> 4904</blockquote> 4905 4906 4907</DD> 4908 4909<DT><b><a name="local_recipient_maps">local_recipient_maps</a> 4910(default: <a href="proxymap.8.html">proxy</a>:unix:passwd.byname $<a href="postconf.5.html#alias_maps">alias_maps</a>)</b></DT><DD> 4911 4912<p> Lookup tables with all names or addresses of local recipients: 4913a recipient address is local when its domain matches $<a href="postconf.5.html#mydestination">mydestination</a>, 4914$<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. Specify @domain as a 4915wild-card for domains that do not have a valid recipient list. 4916Technically, tables listed with $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> are used as 4917lists: Postfix needs to know only if a lookup string is found or 4918not, but it does not use the result from table lookup. </p> 4919 4920<p> 4921If this parameter is non-empty (the default), then the Postfix SMTP 4922server will reject mail for unknown local users. 4923</p> 4924 4925<p> 4926To turn off local recipient checking in the Postfix SMTP server, 4927specify "<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> =" (i.e. empty). 4928</p> 4929 4930<p> 4931The default setting assumes that you use the default Postfix local 4932delivery agent for local delivery. You need to update the 4933<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> setting if: 4934</p> 4935 4936<ul> 4937 4938<li>You redefine the local delivery agent in <a href="master.5.html">master.cf</a>. 4939 4940<li>You redefine the "<a href="postconf.5.html#local_transport">local_transport</a>" setting in <a href="postconf.5.html">main.cf</a>. 4941 4942<li>You use the "<a href="postconf.5.html#luser_relay">luser_relay</a>", "<a href="postconf.5.html#mailbox_transport">mailbox_transport</a>", or "<a href="postconf.5.html#fallback_transport">fallback_transport</a>" 4943feature of the Postfix <a href="local.8.html">local(8)</a> delivery agent. 4944 4945</ul> 4946 4947<p> 4948Details are described in the <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a> file. 4949</p> 4950 4951<p> 4952Beware: if the Postfix SMTP server runs chrooted, you need to access 4953the passwd file via the <a href="proxymap.8.html">proxymap(8)</a> service, in order to overcome 4954chroot access restrictions. The alternative, maintaining a copy of 4955the system password file in the chroot jail is not practical. 4956</p> 4957 4958<p> 4959Examples: 4960</p> 4961 4962<pre> 4963<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = 4964</pre> 4965 4966 4967</DD> 4968 4969<DT><b><a name="local_transport">local_transport</a> 4970(default: <a href="local.8.html">local</a>:$<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 4971 4972<p> The default mail delivery transport and next-hop destination 4973for final delivery to domains listed with <a href="postconf.5.html#mydestination">mydestination</a>, and for 4974[ipaddress] destinations that match $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. 4975This information can be overruled with the <a href="transport.5.html">transport(5)</a> table. </p> 4976 4977<p> 4978By default, local mail is delivered to the transport called "local", 4979which is just the name of a service that is defined the <a href="master.5.html">master.cf</a> file. 4980</p> 4981 4982<p> 4983Specify a string of the form <i>transport:nexthop</i>, where <i>transport</i> 4984is the name of a mail delivery transport defined in <a href="master.5.html">master.cf</a>. 4985The <i>:nexthop</i> destination is optional; its syntax is documented 4986in the manual page of the corresponding delivery agent. 4987</p> 4988 4989<p> 4990Beware: if you override the default local delivery agent then you 4991need to review the <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a> document, otherwise the 4992SMTP server may reject mail for local recipients. 4993</p> 4994 4995 4996</DD> 4997 4998<DT><b><a name="luser_relay">luser_relay</a> 4999(default: empty)</b></DT><DD> 5000 5001<p> 5002Optional catch-all destination for unknown <a href="local.8.html">local(8)</a> recipients. 5003By default, mail for unknown recipients in domains that match 5004$<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> is returned 5005as undeliverable. 5006</p> 5007 5008<p> 5009The following $name expansions are done on <a href="postconf.5.html#luser_relay">luser_relay</a>: 5010</p> 5011 5012<dl> 5013 5014<dt><b>$domain</b></dt> 5015 5016<dd>The recipient domain. </dd> 5017 5018<dt><b>$extension</b></dt> 5019 5020<dd>The recipient address extension. </dd> 5021 5022<dt><b>$home</b></dt> 5023 5024<dd>The recipient's home directory. </dd> 5025 5026<dt><b>$local</b></dt> 5027 5028<dd>The entire recipient address localpart. </dd> 5029 5030<dt><b>$recipient</b></dt> 5031 5032<dd>The full recipient address. </dd> 5033 5034<dt><b>$<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a></b></dt> 5035 5036<dd>The system-wide recipient address extension delimiter. </dd> 5037 5038<dt><b>$shell</b></dt> 5039 5040<dd>The recipient's login shell. </dd> 5041 5042<dt><b>$user</b></dt> 5043 5044<dd>The recipient username. </dd> 5045 5046<dt><b>${name?value}</b></dt> 5047 5048<dd>Expands to <i>value</i> when <i>$name</i> has a non-empty value. </dd> 5049 5050<dt><b>${name:value}</b></dt> 5051 5052<dd>Expands to <i>value</i> when <i>$name</i> has an empty value. </dd> 5053 5054</dl> 5055 5056<p> 5057Instead of $name you can also specify ${name} or $(name). 5058</p> 5059 5060<p> 5061Note: <a href="postconf.5.html#luser_relay">luser_relay</a> works only for the Postfix <a href="local.8.html">local(8)</a> delivery agent. 5062</p> 5063 5064<p> 5065Note: if you use this feature for accounts not in the UNIX password 5066file, then you must specify "<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> =" (i.e. empty) 5067in the <a href="postconf.5.html">main.cf</a> file, otherwise the Postfix SMTP server will reject mail 5068for non-UNIX accounts with "User unknown in local recipient table". 5069</p> 5070 5071<p> 5072Examples: 5073</p> 5074 5075<pre> 5076<a href="postconf.5.html#luser_relay">luser_relay</a> = $user@other.host 5077<a href="postconf.5.html#luser_relay">luser_relay</a> = $local@other.host 5078<a href="postconf.5.html#luser_relay">luser_relay</a> = admin+$local 5079</pre> 5080 5081 5082</DD> 5083 5084<DT><b><a name="mail_name">mail_name</a> 5085(default: Postfix)</b></DT><DD> 5086 5087<p> 5088The mail system name that is displayed in Received: headers, in 5089the SMTP greeting banner, and in bounced mail. 5090</p> 5091 5092 5093</DD> 5094 5095<DT><b><a name="mail_owner">mail_owner</a> 5096(default: postfix)</b></DT><DD> 5097 5098<p> 5099The UNIX system account that owns the Postfix queue and most Postfix 5100daemon processes. Specify the name of a user account that does 5101not share a group with other accounts and that owns no other files 5102or processes on the system. In particular, don't specify nobody 5103or daemon. PLEASE USE A DEDICATED USER ID AND GROUP ID. 5104</p> 5105 5106<p> 5107When this parameter value is changed you need to re-run "<b>postfix 5108set-permissions</b>" (with Postfix version 2.0 and earlier: 5109"<b>/etc/postfix/post-install set-permissions</b>". 5110</p> 5111 5112 5113</DD> 5114 5115<DT><b><a name="mail_release_date">mail_release_date</a> 5116(default: see "postconf -d" output)</b></DT><DD> 5117 5118<p> 5119The Postfix release date, in "YYYYMMDD" format. 5120</p> 5121 5122 5123</DD> 5124 5125<DT><b><a name="mail_spool_directory">mail_spool_directory</a> 5126(default: see "postconf -d" output)</b></DT><DD> 5127 5128<p> 5129The directory where <a href="local.8.html">local(8)</a> UNIX-style mailboxes are kept. The 5130default setting depends on the system type. Specify a name ending 5131in / for maildir-style delivery. 5132</p> 5133 5134<p> 5135Note: maildir delivery is done with the privileges of the recipient. 5136If you use the <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a> setting for maildir style 5137delivery, then you must create the top-level maildir directory in 5138advance. Postfix will not create it. 5139</p> 5140 5141<p> 5142Examples: 5143</p> 5144 5145<pre> 5146<a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a> = /var/mail 5147<a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a> = /var/spool/mail 5148</pre> 5149 5150 5151</DD> 5152 5153<DT><b><a name="mail_version">mail_version</a> 5154(default: see "postconf -d" output)</b></DT><DD> 5155 5156<p> 5157The version of the mail system. Stable releases are named 5158<i>major</i>.<i>minor</i>.<i>patchlevel</i>. Experimental releases 5159also include the release date. The version string can be used in, 5160for example, the SMTP greeting banner. 5161</p> 5162 5163 5164</DD> 5165 5166<DT><b><a name="mailbox_command">mailbox_command</a> 5167(default: empty)</b></DT><DD> 5168 5169<p> 5170Optional external command that the <a href="local.8.html">local(8)</a> delivery agent should 5171use for mailbox delivery. The command is run with the user ID and 5172the primary group ID privileges of the recipient. Exception: 5173command delivery for root executes with $<a href="postconf.5.html#default_privs">default_privs</a> privileges. 5174This is not a problem, because 1) mail for root should always be 5175aliased to a real user and 2) don't log in as root, use "su" instead. 5176</p> 5177 5178<p> 5179The following environment variables are exported to the command: 5180</p> 5181 5182<dl> 5183 5184<dt><b>CLIENT_ADDRESS</b></dt> 5185 5186<dd>Remote client network address. Available in Postfix version 2.2 and 5187later. </dd> 5188 5189<dt><b>CLIENT_HELO</b></dt> 5190 5191<dd>Remote client EHLO command parameter. Available in Postfix version 2.2 5192and later.</dd> 5193 5194<dt><b>CLIENT_HOSTNAME</b></dt> 5195 5196<dd>Remote client hostname. Available in Postfix version 2.2 and later. 5197</dd> 5198 5199<dt><b>CLIENT_PROTOCOL</b></dt> 5200 5201<dd>Remote client protocol. Available in Postfix version 2.2 and later. 5202</dd> 5203 5204<dt><b>DOMAIN</b></dt> 5205 5206<dd>The domain part of the recipient address. </dd> 5207 5208<dt><b>EXTENSION</b></dt> 5209 5210<dd>The optional address extension. </dd> 5211 5212<dt><b>HOME</b></dt> 5213 5214<dd>The recipient home directory. </dd> 5215 5216<dt><b>LOCAL</b></dt> 5217 5218<dd>The recipient address localpart. </dd> 5219 5220<dt><b>LOGNAME</b></dt> 5221 5222<dd>The recipient's username. </dd> 5223 5224<dt><b>ORIGINAL_RECIPIENT</b></dt> 5225 5226<dd>The entire recipient address, before any address rewriting or 5227aliasing. </dd> 5228 5229<dt><b>RECIPIENT</b></dt> 5230 5231<dd>The full recipient address. </dd> 5232 5233<dt><b>SASL_METHOD</b></dt> 5234 5235<dd>SASL authentication method specified in the remote client AUTH 5236command. Available in Postfix version 2.2 and later. </dd> 5237 5238<dt><b>SASL_SENDER</b></dt> 5239 5240<dd>SASL sender address specified in the remote client MAIL FROM 5241command. Available in Postfix version 2.2 and later. </dd> 5242 5243<dt><b>SASL_USER</b></dt> 5244 5245<dd>SASL username specified in the remote client AUTH command. 5246Available in Postfix version 2.2 and later. </dd> 5247 5248<dt><b>SENDER</b></dt> 5249 5250<dd>The full sender address. </dd> 5251 5252<dt><b>SHELL</b></dt> 5253 5254<dd>The recipient's login shell. </dd> 5255 5256<dt><b>USER</b></dt> 5257 5258<dd>The recipient username. </dd> 5259 5260</dl> 5261 5262<p> 5263Unlike other Postfix configuration parameters, the <a href="postconf.5.html#mailbox_command">mailbox_command</a> 5264parameter is not subjected to $name substitutions. This is to make 5265it easier to specify shell syntax (see example below). 5266</p> 5267 5268<p> 5269If you can, avoid shell meta characters because they will force 5270Postfix to run an expensive shell process. If you're delivering 5271via Procmail then running a shell won't make a noticeable difference 5272in the total cost. 5273</p> 5274 5275<p> 5276Note: if you use the <a href="postconf.5.html#mailbox_command">mailbox_command</a> feature to deliver mail 5277system-wide, you must set up an alias that forwards mail for root 5278to a real user. 5279</p> 5280 5281<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 5282is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 5283<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 5284<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 5285 5286<p> 5287Examples: 5288</p> 5289 5290<pre> 5291<a href="postconf.5.html#mailbox_command">mailbox_command</a> = /some/where/procmail 5292<a href="postconf.5.html#mailbox_command">mailbox_command</a> = /some/where/procmail -a "$EXTENSION" 5293<a href="postconf.5.html#mailbox_command">mailbox_command</a> = /some/where/maildrop -d "$USER" 5294 -f "$SENDER" "$EXTENSION" 5295</pre> 5296 5297 5298</DD> 5299 5300<DT><b><a name="mailbox_command_maps">mailbox_command_maps</a> 5301(default: empty)</b></DT><DD> 5302 5303<p> 5304Optional lookup tables with per-recipient external commands to use 5305for <a href="local.8.html">local(8)</a> mailbox delivery. Behavior is as with <a href="postconf.5.html#mailbox_command">mailbox_command</a>. 5306</p> 5307 5308<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 5309is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 5310<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 5311<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 5312 5313 5314</DD> 5315 5316<DT><b><a name="mailbox_delivery_lock">mailbox_delivery_lock</a> 5317(default: see "postconf -d" output)</b></DT><DD> 5318 5319<p> 5320How to lock a UNIX-style <a href="local.8.html">local(8)</a> mailbox before attempting delivery. 5321For a list of available file locking methods, use the "<b>postconf 5322-l</b>" command. 5323</p> 5324 5325<p> 5326This setting is ignored with <b>maildir</b> style delivery, 5327because such deliveries are safe without explicit locks. 5328</p> 5329 5330<p> 5331Note: The <b>dotlock</b> method requires that the recipient UID or 5332GID has write access to the parent directory of the mailbox file. 5333</p> 5334 5335<p> 5336Note: the default setting of this parameter is system dependent. 5337</p> 5338 5339 5340</DD> 5341 5342<DT><b><a name="mailbox_size_limit">mailbox_size_limit</a> 5343(default: 51200000)</b></DT><DD> 5344 5345<p> The maximal size of any <a href="local.8.html">local(8)</a> individual mailbox or maildir 5346file, or zero (no limit). In fact, this limits the size of any 5347file that is written to upon local delivery, including files written 5348by external commands that are executed by the <a href="local.8.html">local(8)</a> delivery 5349agent. </p> 5350 5351<p> 5352This limit must not be smaller than the message size limit. 5353</p> 5354 5355 5356</DD> 5357 5358<DT><b><a name="mailbox_transport">mailbox_transport</a> 5359(default: empty)</b></DT><DD> 5360 5361<p> 5362Optional message delivery transport that the <a href="local.8.html">local(8)</a> delivery 5363agent should use for mailbox delivery to all local recipients, 5364whether or not they are found in the UNIX passwd database. 5365</p> 5366 5367<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 5368is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 5369<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 5370<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 5371 5372 5373</DD> 5374 5375<DT><b><a name="mailbox_transport_maps">mailbox_transport_maps</a> 5376(default: empty)</b></DT><DD> 5377 5378<p> Optional lookup tables with per-recipient message delivery 5379transports to use for <a href="local.8.html">local(8)</a> mailbox delivery, whether or not the 5380recipients are found in the UNIX passwd database. </p> 5381 5382<p> The precedence of <a href="local.8.html">local(8)</a> delivery features from high to low 5383is: aliases, .forward files, <a href="postconf.5.html#mailbox_transport_maps">mailbox_transport_maps</a>, <a href="postconf.5.html#mailbox_transport">mailbox_transport</a>, 5384<a href="postconf.5.html#mailbox_command_maps">mailbox_command_maps</a>, <a href="postconf.5.html#mailbox_command">mailbox_command</a>, <a href="postconf.5.html#home_mailbox">home_mailbox</a>, <a href="postconf.5.html#mail_spool_directory">mail_spool_directory</a>, 5385<a href="postconf.5.html#fallback_transport_maps">fallback_transport_maps</a>, <a href="postconf.5.html#fallback_transport">fallback_transport</a> and <a href="postconf.5.html#luser_relay">luser_relay</a>. </p> 5386 5387<p> For safety reasons, this feature does not allow $number 5388substitutions in regular expression maps. </p> 5389 5390<p> This feature is available in Postfix 2.3 and later. </p> 5391 5392 5393</DD> 5394 5395<DT><b><a name="mailq_path">mailq_path</a> 5396(default: see "postconf -d" output)</b></DT><DD> 5397 5398<p> 5399Sendmail compatibility feature that specifies where the Postfix 5400<a href="mailq.1.html">mailq(1)</a> command is installed. This command can be used to 5401list the Postfix mail queue. 5402</p> 5403 5404 5405</DD> 5406 5407<DT><b><a name="manpage_directory">manpage_directory</a> 5408(default: see "postconf -d" output)</b></DT><DD> 5409 5410<p> 5411Where the Postfix manual pages are installed. 5412</p> 5413 5414 5415</DD> 5416 5417<DT><b><a name="maps_rbl_domains">maps_rbl_domains</a> 5418(default: empty)</b></DT><DD> 5419 5420<p> 5421Obsolete feature: use the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a> feature instead. 5422</p> 5423 5424 5425</DD> 5426 5427<DT><b><a name="maps_rbl_reject_code">maps_rbl_reject_code</a> 5428(default: 554)</b></DT><DD> 5429 5430<p> 5431The numerical Postfix SMTP server response code when a remote SMTP 5432client request is blocked by the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>, <a href="postconf.5.html#reject_rhsbl_client">reject_rhsbl_client</a>, 5433<a href="postconf.5.html#reject_rhsbl_reverse_client">reject_rhsbl_reverse_client</a>, <a href="postconf.5.html#reject_rhsbl_sender">reject_rhsbl_sender</a> or 5434<a href="postconf.5.html#reject_rhsbl_recipient">reject_rhsbl_recipient</a> restriction. 5435</p> 5436 5437<p> 5438Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 5439</p> 5440 5441 5442</DD> 5443 5444<DT><b><a name="masquerade_classes">masquerade_classes</a> 5445(default: envelope_sender, header_sender, header_recipient)</b></DT><DD> 5446 5447<p> 5448What addresses are subject to address masquerading. 5449</p> 5450 5451<p> 5452By default, address masquerading is limited to envelope sender 5453addresses, and to header sender and header recipient addresses. 5454This allows you to use address masquerading on a mail gateway while 5455still being able to forward mail to users on individual machines. 5456</p> 5457 5458<p> 5459Specify zero or more of: envelope_sender, envelope_recipient, 5460header_sender, header_recipient 5461</p> 5462 5463 5464</DD> 5465 5466<DT><b><a name="masquerade_domains">masquerade_domains</a> 5467(default: empty)</b></DT><DD> 5468 5469<p> 5470Optional list of domains whose subdomain structure will be stripped 5471off in email addresses. 5472</p> 5473 5474<p> 5475The list is processed left to right, and processing stops at the 5476first match. Thus, 5477</p> 5478 5479<blockquote> 5480<pre> 5481<a href="postconf.5.html#masquerade_domains">masquerade_domains</a> = foo.example.com example.com 5482</pre> 5483</blockquote> 5484 5485<p> 5486strips "user@any.thing.foo.example.com" to "user@foo.example.com", 5487but strips "user@any.thing.else.example.com" to "user@example.com". 5488</p> 5489 5490<p> 5491A domain name prefixed with ! means do not masquerade this domain 5492or its subdomains. Thus, 5493</p> 5494 5495<blockquote> 5496<pre> 5497<a href="postconf.5.html#masquerade_domains">masquerade_domains</a> = !foo.example.com example.com 5498</pre> 5499</blockquote> 5500 5501<p> 5502does not change "user@any.thing.foo.example.com" or "user@foo.example.com", 5503but strips "user@any.thing.else.example.com" to "user@example.com". 5504</p> 5505 5506<p> Note: with Postfix version 2.2, message header address masquerading 5507happens only when message header address rewriting is enabled: </p> 5508 5509<ul> 5510 5511<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 5512 5513<li> The message is received from a network client that matches 5514$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 5515 5516<li> The message is received from the network, and the 5517<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 5518 5519</ul> 5520 5521<p> To get the behavior before Postfix version 2.2, specify 5522"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 5523 5524<p> 5525Example: 5526</p> 5527 5528<pre> 5529<a href="postconf.5.html#masquerade_domains">masquerade_domains</a> = $<a href="postconf.5.html#mydomain">mydomain</a> 5530</pre> 5531 5532 5533</DD> 5534 5535<DT><b><a name="masquerade_exceptions">masquerade_exceptions</a> 5536(default: empty)</b></DT><DD> 5537 5538<p> 5539Optional list of user names that are not subjected to address 5540masquerading, even when their address matches $<a href="postconf.5.html#masquerade_domains">masquerade_domains</a>. 5541</p> 5542 5543<p> 5544By default, address masquerading makes no exceptions. 5545</p> 5546 5547<p> 5548Specify a list of user names, "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns, 5549separated by commas and/or whitespace. The list is matched left to 5550right, and the search stops on the first match. A "/file/name" 5551pattern is replaced 5552by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a name 5553matches a lookup key (the lookup result is ignored). Continue long 5554lines by starting the next line with whitespace. Specify "!pattern" 5555to exclude a name from the list. The form "!/file/name" is supported 5556only in Postfix version 2.4 and later. </p> 5557 5558<p> 5559Examples: 5560</p> 5561 5562<pre> 5563<a href="postconf.5.html#masquerade_exceptions">masquerade_exceptions</a> = root, mailer-daemon 5564<a href="postconf.5.html#masquerade_exceptions">masquerade_exceptions</a> = root 5565</pre> 5566 5567 5568</DD> 5569 5570<DT><b><a name="master_service_disable">master_service_disable</a> 5571(default: empty)</b></DT><DD> 5572 5573<p> Selectively disable <a href="master.8.html">master(8)</a> listener ports by service type 5574or by service name and type. Specify a list of service types 5575("inet", "unix", "fifo", or "pass") or "name.type" tuples, where 5576"name" is the first field of a <a href="master.5.html">master.cf</a> entry and "type" is a 5577service type. As with other Postfix matchlists, a search stops at 5578the first match. Specify "!pattern" to exclude a service from the 5579list. By default, all <a href="master.8.html">master(8)</a> listener ports are enabled. </p> 5580 5581<p> Note: this feature does not support "/file/name" or "<a href="DATABASE_README.html">type:table</a>" 5582patterns, nor does it support wildcards such as "*" or "all". This 5583is intentional. </p> 5584 5585<p> Examples: </p> 5586 5587<pre> 5588# Turn on all <a href="master.8.html">master(8)</a> listener ports (the default). 5589<a href="postconf.5.html#master_service_disable">master_service_disable</a> = 5590# Turn off only the main SMTP listener port. 5591<a href="postconf.5.html#master_service_disable">master_service_disable</a> = smtp.inet 5592# Turn off all TCP/IP listener ports. 5593<a href="postconf.5.html#master_service_disable">master_service_disable</a> = inet 5594# Turn off all TCP/IP listener ports except "foo". 5595<a href="postconf.5.html#master_service_disable">master_service_disable</a> = !foo.inet, inet 5596</pre> 5597 5598<p> This feature is available in Postfix 2.6 and later. </p> 5599 5600 5601</DD> 5602 5603<DT><b><a name="max_idle">max_idle</a> 5604(default: 100s)</b></DT><DD> 5605 5606<p> 5607The maximum amount of time that an idle Postfix daemon process waits 5608for an incoming connection before terminating voluntarily. This 5609parameter 5610is ignored by the Postfix queue manager and by other long-lived 5611Postfix daemon processes. 5612</p> 5613 5614<p> 5615Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 5616The default time unit is s (seconds). 5617</p> 5618 5619 5620</DD> 5621 5622<DT><b><a name="max_use">max_use</a> 5623(default: 100)</b></DT><DD> 5624 5625<p> 5626The maximal number of incoming connections that a Postfix daemon 5627process will service before terminating voluntarily. This parameter 5628is ignored by the Postfix queue 5629manager and by other long-lived Postfix daemon processes. 5630</p> 5631 5632 5633</DD> 5634 5635<DT><b><a name="maximal_backoff_time">maximal_backoff_time</a> 5636(default: 4000s)</b></DT><DD> 5637 5638<p> 5639The maximal time between attempts to deliver a deferred message. 5640</p> 5641 5642<p> This parameter should be set to a value greater than or equal 5643to $<a href="postconf.5.html#minimal_backoff_time">minimal_backoff_time</a>. See also $<a href="postconf.5.html#queue_run_delay">queue_run_delay</a>. </p> 5644 5645<p> 5646Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 5647The default time unit is s (seconds). 5648</p> 5649 5650 5651</DD> 5652 5653<DT><b><a name="maximal_queue_lifetime">maximal_queue_lifetime</a> 5654(default: 5d)</b></DT><DD> 5655 5656<p> 5657The maximal time a message is queued before it is sent back as 5658undeliverable. 5659</p> 5660 5661<p> 5662Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 5663The default time unit is d (days). 5664</p> 5665 5666<p> 5667Specify 0 when mail delivery should be tried only once. 5668</p> 5669 5670 5671</DD> 5672 5673<DT><b><a name="message_reject_characters">message_reject_characters</a> 5674(default: empty)</b></DT><DD> 5675 5676<p> The set of characters that Postfix will reject in message 5677content. The usual C-like escape sequences are recognized: <tt>\a 5678\b \f \n \r \t \v \<i>ddd</i></tt> (up to three octal digits) and 5679<tt>\\</tt>. </p> 5680 5681<p> Example: </p> 5682 5683<pre> 5684<a href="postconf.5.html#message_reject_characters">message_reject_characters</a> = \0 5685</pre> 5686 5687<p> This feature is available in Postfix 2.3 and later. </p> 5688 5689 5690</DD> 5691 5692<DT><b><a name="message_size_limit">message_size_limit</a> 5693(default: 10240000)</b></DT><DD> 5694 5695<p> 5696The maximal size in bytes of a message, including envelope information. 5697</p> 5698 5699<p> Note: be careful when making changes. Excessively small values 5700will result in the loss of non-delivery notifications, when a bounce 5701message size exceeds the local or remote MTA's message size limit. 5702</p> 5703 5704 5705</DD> 5706 5707<DT><b><a name="message_strip_characters">message_strip_characters</a> 5708(default: empty)</b></DT><DD> 5709 5710<p> The set of characters that Postfix will remove from message 5711content. The usual C-like escape sequences are recognized: <tt>\a 5712\b \f \n \r \t \v \<i>ddd</i></tt> (up to three octal digits) and 5713<tt>\\</tt>. </p> 5714 5715<p> Example: </p> 5716 5717<pre> 5718<a href="postconf.5.html#message_strip_characters">message_strip_characters</a> = \0 5719</pre> 5720 5721<p> This feature is available in Postfix 2.3 and later. </p> 5722 5723 5724</DD> 5725 5726<DT><b><a name="milter_command_timeout">milter_command_timeout</a> 5727(default: 30s)</b></DT><DD> 5728 5729<p> The time limit for sending an SMTP command to a Milter (mail 5730filter) application, and for receiving the response. </p> 5731 5732<p> Specify a non-zero time value (an integral value plus an optional 5733one-letter suffix that specifies the time unit). </p> 5734 5735<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 5736(weeks). The default time unit is s (seconds). </p> 5737 5738<p> This feature is available in Postfix 2.3 and later. </p> 5739 5740 5741</DD> 5742 5743<DT><b><a name="milter_connect_macros">milter_connect_macros</a> 5744(default: see "postconf -d" output)</b></DT><DD> 5745 5746<p> The macros that are sent to Milter (mail filter) applications 5747after completion of an SMTP connection. See <a href="MILTER_README.html">MILTER_README</a> 5748for a list of available macro names and their meanings. </p> 5749 5750<p> This feature is available in Postfix 2.3 and later. </p> 5751 5752 5753</DD> 5754 5755<DT><b><a name="milter_connect_timeout">milter_connect_timeout</a> 5756(default: 30s)</b></DT><DD> 5757 5758<p> The time limit for connecting to a Milter (mail filter) 5759application, and for negotiating protocol options. </p> 5760 5761<p> Specify a non-zero time value (an integral value plus an optional 5762one-letter suffix that specifies the time unit). </p> 5763 5764<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 5765(weeks). The default time unit is s (seconds). </p> 5766 5767<p> This feature is available in Postfix 2.3 and later. </p> 5768 5769 5770</DD> 5771 5772<DT><b><a name="milter_content_timeout">milter_content_timeout</a> 5773(default: 300s)</b></DT><DD> 5774 5775<p> The time limit for sending message content to a Milter (mail 5776filter) application, and for receiving the response. </p> 5777 5778<p> Specify a non-zero time value (an integral value plus an optional 5779one-letter suffix that specifies the time unit). </p> 5780 5781<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 5782(weeks). The default time unit is s (seconds). </p> 5783 5784<p> This feature is available in Postfix 2.3 and later. </p> 5785 5786 5787</DD> 5788 5789<DT><b><a name="milter_data_macros">milter_data_macros</a> 5790(default: see "postconf -d" output)</b></DT><DD> 5791 5792<p> The macros that are sent to version 4 or higher Milter (mail 5793filter) applications after the SMTP DATA command. See <a href="MILTER_README.html">MILTER_README</a> 5794for a list of available macro names and their meanings. </p> 5795 5796<p> This feature is available in Postfix 2.3 and later. </p> 5797 5798 5799</DD> 5800 5801<DT><b><a name="milter_default_action">milter_default_action</a> 5802(default: tempfail)</b></DT><DD> 5803 5804<p> The default action when a Milter (mail filter) application is 5805unavailable or mis-configured. Specify one of the following: </p> 5806 5807<dl compact> 5808 5809<dt>accept</dt> <dd>Proceed as if the mail filter was not present. 5810</dd> 5811 5812<dt>reject</dt> <dd>Reject all further commands in this session 5813with a permanent status code.</dd> 5814 5815<dt>tempfail</dt> <dd>Reject all further commands in this session 5816with a temporary status code. </dd> 5817 5818<dt>quarantine</dt> <dd>Like "accept", but freeze the message in 5819the "<a href="QSHAPE_README.html#hold_queue">hold" queue</a>. Available with Postfix 2.6 and later. </dd> 5820 5821</dl> 5822 5823<p> This feature is available in Postfix 2.3 and later. </p> 5824 5825 5826</DD> 5827 5828<DT><b><a name="milter_end_of_data_macros">milter_end_of_data_macros</a> 5829(default: see "postconf -d" output)</b></DT><DD> 5830 5831<p> The macros that are sent to Milter (mail filter) applications 5832after the message end-of-data. See <a href="MILTER_README.html">MILTER_README</a> for a list of 5833available macro names and their meanings. </p> 5834 5835<p> This feature is available in Postfix 2.3 and later. </p> 5836 5837 5838</DD> 5839 5840<DT><b><a name="milter_end_of_header_macros">milter_end_of_header_macros</a> 5841(default: see "postconf -d" output)</b></DT><DD> 5842 5843<p> The macros that are sent to Milter (mail filter) applications 5844after the end of the message header. See <a href="MILTER_README.html">MILTER_README</a> for a list 5845of available macro names and their meanings. </p> 5846 5847<p> This feature is available in Postfix 2.5 and later. </p> 5848 5849 5850</DD> 5851 5852<DT><b><a name="milter_header_checks">milter_header_checks</a> 5853(default: empty)</b></DT><DD> 5854 5855<p> Optional lookup tables for content inspection of message headers 5856that are produced by Milter applications. See the <a href="header_checks.5.html">header_checks(5)</a> 5857manual page available actions. Currently, PREPEND is not implemented. 5858</p> 5859 5860<p> The following example sends all mail that is marked as SPAM to 5861a spam handling machine. Note that matches are case-insensitive 5862by default. </p> 5863 5864<pre> 5865/etc/postfix/<a href="postconf.5.html">main.cf</a>: 5866 <a href="postconf.5.html#milter_header_checks">milter_header_checks</a> = <a href="pcre_table.5.html">pcre</a>:/etc/postfix/<a href="postconf.5.html#milter_header_checks">milter_header_checks</a> 5867</pre> 5868 5869<pre> 5870/etc/postfix/<a href="postconf.5.html#milter_header_checks">milter_header_checks</a>: 5871 /^X-SPAM-FLAG:\s+YES/ FILTER mysmtp:sanitizer.example.com:25 5872</pre> 5873 5874<p> The <a href="postconf.5.html#milter_header_checks">milter_header_checks</a> mechanism could also be used for 5875whitelisting. For example it could be used to skip heavy content 5876inspection for DKIM-signed mail from known friendly domains. </p> 5877 5878<p> This feature is available in Postfix 2.7, and as an optional 5879patch for Postfix 2.6. </p> 5880 5881 5882</DD> 5883 5884<DT><b><a name="milter_helo_macros">milter_helo_macros</a> 5885(default: see "postconf -d" output)</b></DT><DD> 5886 5887<p> The macros that are sent to Milter (mail filter) applications 5888after the SMTP HELO or EHLO command. See 5889<a href="MILTER_README.html">MILTER_README</a> for a list of available macro names and their meanings. 5890</p> 5891 5892<p> This feature is available in Postfix 2.3 and later. </p> 5893 5894 5895</DD> 5896 5897<DT><b><a name="milter_macro_daemon_name">milter_macro_daemon_name</a> 5898(default: $<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 5899 5900<p> The {daemon_name} macro value for Milter (mail filter) applications. 5901See <a href="MILTER_README.html">MILTER_README</a> for a list of available macro names and their 5902meanings. </p> 5903 5904<p> This feature is available in Postfix 2.3 and later. </p> 5905 5906 5907</DD> 5908 5909<DT><b><a name="milter_macro_v">milter_macro_v</a> 5910(default: $<a href="postconf.5.html#mail_name">mail_name</a> $<a href="postconf.5.html#mail_version">mail_version</a>)</b></DT><DD> 5911 5912<p> The {v} macro value for Milter (mail filter) applications. 5913See <a href="MILTER_README.html">MILTER_README</a> for a list of available macro names and their 5914meanings. </p> 5915 5916<p> This feature is available in Postfix 2.3 and later. </p> 5917 5918 5919</DD> 5920 5921<DT><b><a name="milter_mail_macros">milter_mail_macros</a> 5922(default: see "postconf -d" output)</b></DT><DD> 5923 5924<p> The macros that are sent to Milter (mail filter) applications 5925after the SMTP MAIL FROM command. See <a href="MILTER_README.html">MILTER_README</a> 5926for a list of available macro names and their meanings. </p> 5927 5928<p> This feature is available in Postfix 2.3 and later. </p> 5929 5930 5931</DD> 5932 5933<DT><b><a name="milter_protocol">milter_protocol</a> 5934(default: 6)</b></DT><DD> 5935 5936<p> The mail filter protocol version and optional protocol extensions 5937for communication with a Milter application; prior to Postfix 2.6 5938the default protocol is 2. Postfix 5939sends this version number during the initial protocol handshake. 5940It should match the version number that is expected by the mail 5941filter application (or by its Milter library). </p> 5942 5943<p>Protocol versions: </p> 5944 5945<dl compact> 5946 5947<dt>2</dt> <dd>Use Sendmail 8 mail filter protocol version 2 (default 5948with Sendmail version 8.11 .. 8.13 and Postfix version 2.3 .. 59492.5).</dd> 5950 5951<dt>3</dt> <dd>Use Sendmail 8 mail filter protocol version 3.</dd> 5952 5953<dt>4</dt> <dd>Use Sendmail 8 mail filter protocol version 4.</dd> 5954 5955<dt>6</dt> <dd>Use Sendmail 8 mail filter protocol version 6 (default 5956with Sendmail version 8.14 and Postfix version 2.6).</dd> 5957 5958</dl> 5959 5960<p>Protocol extensions: </p> 5961 5962<dl compact> 5963 5964<dt>no_header_reply</dt> <dd> Specify this when the Milter application 5965will not reply for each individual message header.</dd> 5966 5967</dl> 5968 5969<p> This feature is available in Postfix 2.3 and later. </p> 5970 5971 5972</DD> 5973 5974<DT><b><a name="milter_rcpt_macros">milter_rcpt_macros</a> 5975(default: see "postconf -d" output)</b></DT><DD> 5976 5977<p> The macros that are sent to Milter (mail filter) applications 5978after the SMTP RCPT TO command. See <a href="MILTER_README.html">MILTER_README</a> 5979for a list of available macro names and their meanings. </p> 5980 5981<p> This feature is available in Postfix 2.3 and later. </p> 5982 5983 5984</DD> 5985 5986<DT><b><a name="milter_unknown_command_macros">milter_unknown_command_macros</a> 5987(default: see "postconf -d" output)</b></DT><DD> 5988 5989<p> The macros that are sent to version 3 or higher Milter (mail 5990filter) applications after an unknown SMTP command. See <a href="MILTER_README.html">MILTER_README</a> 5991for a list of available macro names and their meanings. </p> 5992 5993<p> This feature is available in Postfix 2.3 and later. </p> 5994 5995 5996</DD> 5997 5998<DT><b><a name="mime_boundary_length_limit">mime_boundary_length_limit</a> 5999(default: 2048)</b></DT><DD> 6000 6001<p> 6002The maximal length of MIME multipart boundary strings. The MIME 6003processor is unable to distinguish between boundary strings that 6004do not differ in the first $<a href="postconf.5.html#mime_boundary_length_limit">mime_boundary_length_limit</a> characters. 6005</p> 6006 6007<p> 6008This feature is available in Postfix 2.0 and later. 6009</p> 6010 6011 6012</DD> 6013 6014<DT><b><a name="mime_header_checks">mime_header_checks</a> 6015(default: $<a href="postconf.5.html#header_checks">header_checks</a>)</b></DT><DD> 6016 6017<p> 6018Optional lookup tables for content inspection of MIME related 6019message headers, as described in the <a href="header_checks.5.html">header_checks(5)</a> manual page. 6020</p> 6021 6022<p> 6023This feature is available in Postfix 2.0 and later. 6024</p> 6025 6026 6027</DD> 6028 6029<DT><b><a name="mime_nesting_limit">mime_nesting_limit</a> 6030(default: 100)</b></DT><DD> 6031 6032<p> 6033The maximal recursion level that the MIME processor will handle. 6034Postfix refuses mail that is nested deeper than the specified limit. 6035</p> 6036 6037<p> 6038This feature is available in Postfix 2.0 and later. 6039</p> 6040 6041 6042</DD> 6043 6044<DT><b><a name="minimal_backoff_time">minimal_backoff_time</a> 6045(default: 300s)</b></DT><DD> 6046 6047<p> 6048The minimal time between attempts to deliver a deferred message; 6049prior to Postfix 2.4 the default value was 1000s. 6050</p> 6051 6052<p> 6053This parameter also limits the time an unreachable destination is 6054kept in the short-term, in-memory, destination status cache. 6055</p> 6056 6057<p> This parameter should be set greater than or equal to 6058$<a href="postconf.5.html#queue_run_delay">queue_run_delay</a>. See also $<a href="postconf.5.html#maximal_backoff_time">maximal_backoff_time</a>. </p> 6059 6060<p> 6061Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 6062The default time unit is s (seconds). 6063</p> 6064 6065 6066</DD> 6067 6068<DT><b><a name="multi_instance_directories">multi_instance_directories</a> 6069(default: empty)</b></DT><DD> 6070 6071<p> An optional list of non-default Postfix configuration directories; 6072these directories belong to additional Postfix instances that share 6073the Postfix executable files and documentation with the default 6074Postfix instance, and that are started, stopped, etc., together 6075with the default Postfix instance. Specify a list of pathnames 6076separated by comma or whitespace. </p> 6077 6078<p> When $<a href="postconf.5.html#multi_instance_directories">multi_instance_directories</a> is empty, the <a href="postfix.1.html">postfix(1)</a> command 6079runs in single-instance mode and operates on a single Postfix 6080instance only. Otherwise, the <a href="postfix.1.html">postfix(1)</a> command runs in multi-instance 6081mode and invokes the multi-instance manager specified with the 6082<a href="postconf.5.html#multi_instance_wrapper">multi_instance_wrapper</a> parameter. The multi-instance manager in 6083turn executes <a href="postfix.1.html">postfix(1)</a> commands for the default instance and for 6084all Postfix instances in $<a href="postconf.5.html#multi_instance_directories">multi_instance_directories</a>. </p> 6085 6086<p> Currently, this parameter setting is ignored except for the 6087default <a href="postconf.5.html">main.cf</a> file. </p> 6088 6089<p> This feature is available in Postfix 2.6 and later. </p> 6090 6091 6092</DD> 6093 6094<DT><b><a name="multi_instance_enable">multi_instance_enable</a> 6095(default: no)</b></DT><DD> 6096 6097<p> Allow this Postfix instance to be started, stopped, etc., by a 6098multi-instance manager. By default, new instances are created in 6099a safe state that prevents them from being started inadvertently. 6100This parameter is reserved for the multi-instance manager. </p> 6101 6102<p> This feature is available in Postfix 2.6 and later. </p> 6103 6104 6105</DD> 6106 6107<DT><b><a name="multi_instance_group">multi_instance_group</a> 6108(default: empty)</b></DT><DD> 6109 6110<p> The optional instance group name of this Postfix instance. A 6111group identifies closely-related Postfix instances that the 6112multi-instance manager can start, stop, etc., as a unit. This 6113parameter is reserved for the multi-instance manager. </p> 6114 6115<p> This feature is available in Postfix 2.6 and later. </p> 6116 6117 6118</DD> 6119 6120<DT><b><a name="multi_instance_name">multi_instance_name</a> 6121(default: empty)</b></DT><DD> 6122 6123<p> The optional instance name of this Postfix instance. This name 6124becomes also the default value for the <a href="postconf.5.html#syslog_name">syslog_name</a> parameter. </p> 6125 6126<p> This feature is available in Postfix 2.6 and later. </p> 6127 6128 6129</DD> 6130 6131<DT><b><a name="multi_instance_wrapper">multi_instance_wrapper</a> 6132(default: empty)</b></DT><DD> 6133 6134<p> The pathname of a multi-instance manager command that the 6135<a href="postfix.1.html">postfix(1)</a> command invokes when the <a href="postconf.5.html#multi_instance_directories">multi_instance_directories</a> 6136parameter value is non-empty. The pathname may be followed by 6137initial command arguments separated by whitespace; shell 6138metacharacters such as quotes are not supported in this context. 6139</p> 6140 6141<p> The <a href="postfix.1.html">postfix(1)</a> command invokes the manager command with the 6142<a href="postfix.1.html">postfix(1)</a> non-option command arguments on the manager command line, 6143and with all installation configuration parameters exported into 6144the manager command process environment. The manager command in 6145turn invokes the <a href="postfix.1.html">postfix(1)</a> command for individual Postfix instances 6146as "postfix -c <i><a href="postconf.5.html#config_directory">config_directory</a></i> <i>command</i>". </p> 6147 6148<p> This feature is available in Postfix 2.6 and later. </p> 6149 6150 6151</DD> 6152 6153<DT><b><a name="multi_recipient_bounce_reject_code">multi_recipient_bounce_reject_code</a> 6154(default: 550)</b></DT><DD> 6155 6156<p> 6157The numerical Postfix SMTP server response code when a remote SMTP 6158client request is blocked by the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipient_bounce</a> 6159restriction. 6160</p> 6161 6162<p> 6163Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 6164</p> 6165 6166<p> 6167This feature is available in Postfix 2.1 and later. 6168</p> 6169 6170 6171</DD> 6172 6173<DT><b><a name="mydestination">mydestination</a> 6174(default: $<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a>, localhost)</b></DT><DD> 6175 6176<p> The list of domains that are delivered via the $<a href="postconf.5.html#local_transport">local_transport</a> 6177mail delivery transport. By default this is the Postfix <a href="local.8.html">local(8)</a> 6178delivery agent which looks up all recipients in /etc/passwd and 6179/etc/aliases. The SMTP server validates recipient addresses with 6180$<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> and rejects non-existent recipients. See also 6181the <a href="ADDRESS_CLASS_README.html#local_domain_class">local domain</a> class in the <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> file. 6182</p> 6183 6184<p> 6185The default <a href="postconf.5.html#mydestination">mydestination</a> value specifies names for the local 6186machine only. On a mail domain gateway, you should also include 6187$<a href="postconf.5.html#mydomain">mydomain</a>. 6188</p> 6189 6190<p> 6191The $<a href="postconf.5.html#local_transport">local_transport</a> delivery method is also selected for mail 6192addressed to user@[the.net.work.address] of the mail system (the 6193IP addresses specified with the <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> and <a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> 6194parameters). 6195</p> 6196 6197<p> 6198Warnings: 6199</p> 6200 6201<ul> 6202 6203<li><p>Do not specify the names of virtual domains - those domains 6204are specified elsewhere. See <a href="VIRTUAL_README.html">VIRTUAL_README</a> for more information. </p> 6205 6206<li><p>Do not specify the names of domains that this machine is 6207backup MX host for. See <a href="STANDARD_CONFIGURATION_README.html">STANDARD_CONFIGURATION_README</a> for how to 6208set up backup MX hosts. </p> 6209 6210<li><p>By default, the Postfix SMTP server rejects mail for recipients 6211not listed with the <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> parameter. See the 6212<a href="postconf.5.html">postconf(5)</a> manual for a description of the <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> 6213and <a href="postconf.5.html#unknown_local_recipient_reject_code">unknown_local_recipient_reject_code</a> parameters. </p> 6214 6215</ul> 6216 6217<p> 6218Specify a list of host or domain names, "/file/name" or "<a href="DATABASE_README.html">type:table</a>" 6219patterns, separated by commas and/or whitespace. A "/file/name" 6220pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table 6221is matched when a name matches a lookup key (the lookup result is 6222ignored). Continue long lines by starting the next line with 6223whitespace. </p> 6224 6225<p> 6226Examples: 6227</p> 6228 6229<pre> 6230<a href="postconf.5.html#mydestination">mydestination</a> = $<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a> $<a href="postconf.5.html#mydomain">mydomain</a> 6231<a href="postconf.5.html#mydestination">mydestination</a> = $<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a> www.$<a href="postconf.5.html#mydomain">mydomain</a>, ftp.$<a href="postconf.5.html#mydomain">mydomain</a> 6232</pre> 6233 6234 6235</DD> 6236 6237<DT><b><a name="mydomain">mydomain</a> 6238(default: see "postconf -d" output)</b></DT><DD> 6239 6240<p> 6241The internet domain name of this mail system. The default is to 6242use $<a href="postconf.5.html#myhostname">myhostname</a> minus the first component, or "localdomain" (Postfix 62432.3 and later). $<a href="postconf.5.html#mydomain">mydomain</a> is used as 6244a default value for many other configuration parameters. 6245</p> 6246 6247<p> 6248Example: 6249</p> 6250 6251<pre> 6252<a href="postconf.5.html#mydomain">mydomain</a> = domain.tld 6253</pre> 6254 6255 6256</DD> 6257 6258<DT><b><a name="myhostname">myhostname</a> 6259(default: see "postconf -d" output)</b></DT><DD> 6260 6261<p> 6262The internet hostname of this mail system. The default is to use 6263the fully-qualified domain name (FQDN) from gethostname(), or to 6264use the non-FQDN result from gethostname() and append ".$<a href="postconf.5.html#mydomain">mydomain</a>". 6265$<a href="postconf.5.html#myhostname">myhostname</a> is used as a default value for many other configuration 6266parameters. </p> 6267 6268<p> 6269Example: 6270</p> 6271 6272<pre> 6273<a href="postconf.5.html#myhostname">myhostname</a> = host.example.com 6274</pre> 6275 6276 6277</DD> 6278 6279<DT><b><a name="mynetworks">mynetworks</a> 6280(default: see "postconf -d" output)</b></DT><DD> 6281 6282<p> 6283The list of "trusted" SMTP clients that have more privileges than 6284"strangers". 6285</p> 6286 6287<p> 6288In particular, "trusted" SMTP clients are allowed to relay mail 6289through Postfix. See the <a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> parameter 6290description in the <a href="postconf.5.html">postconf(5)</a> manual. 6291</p> 6292 6293<p> 6294You can specify the list of "trusted" network addresses by hand 6295or you can let Postfix do it for you (which is the default). 6296See the description of the <a href="postconf.5.html#mynetworks_style">mynetworks_style</a> parameter for more 6297information. 6298</p> 6299 6300<p> 6301If you specify the <a href="postconf.5.html#mynetworks">mynetworks</a> list by hand, 6302Postfix ignores the <a href="postconf.5.html#mynetworks_style">mynetworks_style</a> setting. 6303</p> 6304 6305<p> Specify a list of network addresses or network/netmask patterns, 6306separated by commas and/or whitespace. Continue long lines by 6307starting the next line with whitespace. </p> 6308 6309<p> The netmask specifies the number of bits in the network part 6310of a host address. You can also specify "/file/name" or "<a href="DATABASE_README.html">type:table</a>" 6311patterns. A "/file/name" pattern is replaced by its contents; a 6312"<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a table entry matches a 6313lookup string (the lookup result is ignored). </p> 6314 6315<p> The list is matched left to right, and the search stops on the 6316first match. Specify "!pattern" to exclude an address or network 6317block from the list. The form "!/file/name" is supported only 6318in Postfix version 2.4 and later. </p> 6319 6320<p> Note: IP version 6 address information must be specified inside 6321<tt>[]</tt> in the <a href="postconf.5.html#mynetworks">mynetworks</a> value, and in files specified with 6322"/file/name". IP version 6 addresses contain the ":" character, 6323and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" pattern. </p> 6324 6325<p> Examples: </p> 6326 6327<pre> 6328<a href="postconf.5.html#mynetworks">mynetworks</a> = 127.0.0.0/8 168.100.189.0/28 6329<a href="postconf.5.html#mynetworks">mynetworks</a> = !192.168.0.1, 192.168.0.0/28 6330<a href="postconf.5.html#mynetworks">mynetworks</a> = 127.0.0.0/8 168.100.189.0/28 [::1]/128 [2001:240:587::]/64 6331<a href="postconf.5.html#mynetworks">mynetworks</a> = $<a href="postconf.5.html#config_directory">config_directory</a>/mynetworks 6332<a href="postconf.5.html#mynetworks">mynetworks</a> = hash:/etc/postfix/network_table 6333</pre> 6334 6335 6336</DD> 6337 6338<DT><b><a name="mynetworks_style">mynetworks_style</a> 6339(default: subnet)</b></DT><DD> 6340 6341<p> 6342The method to generate the default value for the <a href="postconf.5.html#mynetworks">mynetworks</a> parameter. 6343This is the list of trusted networks for relay access control etc. 6344</p> 6345 6346<ul> 6347 6348<li><p>Specify "<a href="postconf.5.html#mynetworks_style">mynetworks_style</a> = host" when Postfix should 6349"trust" only the local machine. </p> 6350 6351<li><p>Specify "<a href="postconf.5.html#mynetworks_style">mynetworks_style</a> = subnet" when Postfix 6352should "trust" SMTP clients in the same IP subnetworks as the local 6353machine. On Linux, this works correctly only with interfaces 6354specified with the "ifconfig" command. </p> 6355 6356<li><p>Specify "<a href="postconf.5.html#mynetworks_style">mynetworks_style</a> = class" when Postfix should 6357"trust" SMTP clients in the same IP class A/B/C networks as the 6358local machine. Don't do this with a dialup site - it would cause 6359Postfix to "trust" your entire provider's network. Instead, specify 6360an explicit <a href="postconf.5.html#mynetworks">mynetworks</a> list by hand, as described with the <a href="postconf.5.html#mynetworks">mynetworks</a> 6361configuration parameter. </p> 6362 6363</ul> 6364 6365 6366</DD> 6367 6368<DT><b><a name="myorigin">myorigin</a> 6369(default: $<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 6370 6371<p> 6372The domain name that locally-posted mail appears to come 6373from, and that locally posted mail is delivered to. The default, 6374$<a href="postconf.5.html#myhostname">myhostname</a>, is adequate for small sites. If you run a domain with 6375multiple machines, you should (1) change this to $<a href="postconf.5.html#mydomain">mydomain</a> and (2) 6376set up a domain-wide alias database that aliases each user to 6377user@that.users.mailhost. 6378</p> 6379 6380<p> 6381Example: 6382</p> 6383 6384<pre> 6385<a href="postconf.5.html#myorigin">myorigin</a> = $<a href="postconf.5.html#mydomain">mydomain</a> 6386</pre> 6387 6388 6389</DD> 6390 6391<DT><b><a name="nested_header_checks">nested_header_checks</a> 6392(default: $<a href="postconf.5.html#header_checks">header_checks</a>)</b></DT><DD> 6393 6394<p> 6395Optional lookup tables for content inspection of non-MIME message 6396headers in attached messages, as described in the <a href="header_checks.5.html">header_checks(5)</a> 6397manual page. 6398</p> 6399 6400<p> 6401This feature is available in Postfix 2.0 and later. 6402</p> 6403 6404 6405</DD> 6406 6407<DT><b><a name="newaliases_path">newaliases_path</a> 6408(default: see "postconf -d" output)</b></DT><DD> 6409 6410<p> 6411Sendmail compatibility feature that specifies the location of the 6412<a href="newaliases.1.html">newaliases(1)</a> command. This command can be used to rebuild the 6413<a href="local.8.html">local(8)</a> <a href="aliases.5.html">aliases(5)</a> database. 6414</p> 6415 6416 6417</DD> 6418 6419<DT><b><a name="non_fqdn_reject_code">non_fqdn_reject_code</a> 6420(default: 504)</b></DT><DD> 6421 6422<p> 6423The numerical Postfix SMTP server reply code when a client request 6424is rejected by the <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>, <a href="postconf.5.html#reject_non_fqdn_sender">reject_non_fqdn_sender</a> 6425or <a href="postconf.5.html#reject_non_fqdn_recipient">reject_non_fqdn_recipient</a> restriction. 6426</p> 6427 6428 6429</DD> 6430 6431<DT><b><a name="non_smtpd_milters">non_smtpd_milters</a> 6432(default: empty)</b></DT><DD> 6433 6434<p> A list of Milter (mail filter) applications for new mail that 6435does not arrive via the Postfix <a href="smtpd.8.html">smtpd(8)</a> server. This includes local 6436submission via the <a href="sendmail.1.html">sendmail(1)</a> command line, new mail that arrives 6437via the Postfix <a href="qmqpd.8.html">qmqpd(8)</a> server, and old mail that is re-injected 6438into the queue with "postsuper -r". See the <a href="MILTER_README.html">MILTER_README</a> document 6439for details. </p> 6440 6441<p> This feature is available in Postfix 2.3 and later. </p> 6442 6443 6444</DD> 6445 6446<DT><b><a name="notify_classes">notify_classes</a> 6447(default: resource, software)</b></DT><DD> 6448 6449<p> 6450The list of error classes that are reported to the postmaster. The 6451default is to report only the most serious problems. The paranoid 6452may wish to turn on the policy (UCE and mail relaying) and protocol 6453error (broken mail software) reports. 6454</p> 6455 6456<p> NOTE: postmaster notifications may contain confidential information 6457such as SASL passwords or message content. It is the system 6458administrator's responsibility to treat such information with care. 6459</p> 6460 6461<p> 6462The error classes are: 6463</p> 6464 6465<dl> 6466 6467<dt><b>bounce</b> (also implies <b>2bounce</b>)</dt> 6468 6469<dd>Send the postmaster copies of the headers of bounced mail, and 6470send transcripts of SMTP sessions when Postfix rejects mail. The 6471notification is sent to the address specified with the 6472<a href="postconf.5.html#bounce_notice_recipient">bounce_notice_recipient</a> configuration parameter (default: postmaster). 6473</dd> 6474 6475<dt><b>2bounce</b></dt> 6476 6477<dd>Send undeliverable bounced mail to the postmaster. The notification 6478is sent to the address specified with the <a href="postconf.5.html#2bounce_notice_recipient">2bounce_notice_recipient</a> 6479configuration parameter (default: postmaster). </dd> 6480 6481<dt><b>delay</b></dt> 6482 6483<dd>Send the postmaster copies of the headers of delayed mail. The 6484notification is sent to the address specified with the 6485<a href="postconf.5.html#delay_notice_recipient">delay_notice_recipient</a> configuration parameter (default: postmaster). 6486</dd> 6487 6488<dt><b>policy</b></dt> 6489 6490<dd>Send the postmaster a transcript of the SMTP session when a 6491client request was rejected because of (UCE) policy. The notification 6492is sent to the address specified with the <a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> 6493configuration parameter (default: postmaster). </dd> 6494 6495<dt><b>protocol</b></dt> 6496 6497<dd>Send the postmaster a transcript of the SMTP session in case 6498of client or server protocol errors. The notification is sent to 6499the address specified with the <a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> configuration 6500parameter (default: postmaster). </dd> 6501 6502<dt><b>resource</b></dt> 6503 6504<dd>Inform the postmaster of mail not delivered due to resource 6505problems. The notification is sent to the address specified with 6506the <a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> configuration parameter (default: 6507postmaster). </dd> 6508 6509<dt><b>software</b></dt> 6510 6511<dd>Inform the postmaster of mail not delivered due to software 6512problems. The notification is sent to the address specified with 6513the <a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> configuration parameter (default: 6514postmaster). </dd> 6515 6516</dl> 6517 6518<p> 6519Examples: 6520</p> 6521 6522<pre> 6523<a href="postconf.5.html#notify_classes">notify_classes</a> = bounce, delay, policy, protocol, resource, software 6524<a href="postconf.5.html#notify_classes">notify_classes</a> = 2bounce, resource, software 6525</pre> 6526 6527 6528</DD> 6529 6530<DT><b><a name="owner_request_special">owner_request_special</a> 6531(default: yes)</b></DT><DD> 6532 6533<p> 6534Give special treatment to owner-listname and listname-request 6535address localparts: don't split such addresses when the 6536<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> is set to "-". This feature is useful for 6537mailing lists. 6538</p> 6539 6540 6541</DD> 6542 6543<DT><b><a name="parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> 6544(default: see "postconf -d" output)</b></DT><DD> 6545 6546<p> 6547What Postfix features match subdomains of "domain.tld" automatically, 6548instead of requiring an explicit ".domain.tld" pattern. This is 6549planned backwards compatibility: eventually, all Postfix features 6550are expected to require explicit ".domain.tld" style patterns when 6551you really want to match subdomains. 6552</p> 6553 6554 6555</DD> 6556 6557<DT><b><a name="permit_mx_backup_networks">permit_mx_backup_networks</a> 6558(default: empty)</b></DT><DD> 6559 6560<p> 6561Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to 6562only domains whose primary MX hosts match the listed networks. 6563The parameter value syntax is the same as with the <a href="postconf.5.html#mynetworks">mynetworks</a> 6564parameter; note, however, that the default value is empty. </p> 6565 6566 6567</DD> 6568 6569<DT><b><a name="pickup_service_name">pickup_service_name</a> 6570(default: pickup)</b></DT><DD> 6571 6572<p> 6573The name of the <a href="pickup.8.html">pickup(8)</a> service. This service picks up local mail 6574submissions from the Postfix <a href="QSHAPE_README.html#maildrop_queue">maildrop queue</a>. 6575</p> 6576 6577<p> 6578This feature is available in Postfix 2.0 and later. 6579</p> 6580 6581 6582</DD> 6583 6584<DT><b><a name="plaintext_reject_code">plaintext_reject_code</a> 6585(default: 450)</b></DT><DD> 6586 6587<p> 6588The numerical Postfix SMTP server response code when a request 6589is rejected by the <b><a href="postconf.5.html#reject_plaintext_session">reject_plaintext_session</a></b> restriction. 6590</p> 6591 6592<p> This feature is available in Postfix 2.3 and later. </p> 6593 6594 6595</DD> 6596 6597<DT><b><a name="postmulti_control_commands">postmulti_control_commands</a> 6598(default: reload flush)</b></DT><DD> 6599 6600<p> The <a href="postfix.1.html">postfix(1)</a> commands that the <a href="postmulti.1.html">postmulti(1)</a> instance manager 6601treats as "control" commands, that operate on running instances. For 6602these commands, disabled instances are skipped. </p> 6603 6604<p> This feature is available in Postfix 2.6 and later. </p> 6605 6606 6607</DD> 6608 6609<DT><b><a name="postmulti_start_commands">postmulti_start_commands</a> 6610(default: start)</b></DT><DD> 6611 6612<p> The <a href="postfix.1.html">postfix(1)</a> commands that the <a href="postmulti.1.html">postmulti(1)</a> instance manager treats 6613as "start" commands. For these commands, disabled instances are "checked" 6614rather than "started", and failure to "start" a member instance of an 6615instance group will abort the start-up of later instances. </p> 6616 6617<p> This feature is available in Postfix 2.6 and later. </p> 6618 6619 6620</DD> 6621 6622<DT><b><a name="postmulti_stop_commands">postmulti_stop_commands</a> 6623(default: see "postconf -d" output)</b></DT><DD> 6624 6625<p> The <a href="postfix.1.html">postfix(1)</a> commands that the <a href="postmulti.1.html">postmulti(1)</a> instance manager treats 6626as "stop" commands. For these commands, disabled instances are skipped, 6627and enabled instances are processed in reverse order. </p> 6628 6629<p> This feature is available in Postfix 2.6 and later. </p> 6630 6631 6632</DD> 6633 6634<DT><b><a name="postscreen_access_list">postscreen_access_list</a> 6635(default: <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>)</b></DT><DD> 6636 6637<p> Permanent white/blacklist for remote SMTP client IP addresses. 6638<a href="postscreen.8.html">postscreen(8)</a> searches this list immediately after a remote SMTP 6639client connects. Specify a comma- or whitespace-separated list of 6640commands (in upper or lower case) or lookup tables. The search stops 6641upon the first command that fires for the client IP address. </p> 6642 6643<dl> 6644 6645<dt> <b> <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a> </b> </dt> <dd> Whitelist the client and 6646terminate the search if the client IP address matches $<a href="postconf.5.html#mynetworks">mynetworks</a>. 6647Do not subject the client to any before/after 220 greeting tests. 6648Pass the connection immediately to a Postfix SMTP server process. 6649</dd> 6650 6651<dt> <b> <a href="DATABASE_README.html">type:table</a> </b> </dt> <dd> Query the specified lookup 6652table. Each table lookup result is an access list, except that 6653access lists inside a table cannot specify <a href="DATABASE_README.html">type:table</a> entries. <br> 6654To discourage the use of hash, btree, etc. tables, there is no 6655support for substring matching like <a href="smtpd.8.html">smtpd(8)</a>. Use CIDR tables 6656instead. </dd> 6657 6658<dt> <b> permit </b> </dt> <dd> Whitelist the client and terminate 6659the search. Do not subject the client to any before/after 220 6660greeting tests. Pass the connection immediately to a Postfix SMTP 6661server process. </dd> 6662 6663<dt> <b> reject </b> </dt> <dd> Blacklist the client and terminate 6664the search. Subject the client to the action configured with the 6665<a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> configuration parameter. </dd> 6666 6667<dt> <b> dunno </b> </dt> <dd> All <a href="postscreen.8.html">postscreen(8)</a> access lists 6668implicitly have this command at the end. <br> When <b> dunno </b> 6669is executed inside a lookup table, return from the lookup table and 6670evaluate the next command. <br> When <b> dunno </b> is executed 6671outside a lookup table, terminate the search, and subject the client 6672to the configured before/after 220 greeting tests. </dd> 6673 6674</dl> 6675 6676<p> Example: </p> 6677 6678<pre> 6679/etc/postfix/<a href="postconf.5.html">main.cf</a>: 6680 <a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, 6681 <a href="cidr_table.5.html">cidr</a>:/etc/postfix/postscreen_access.cidr 6682</pre> 6683 6684<pre> 6685/etc/postfix/postscreen_access.<a href="cidr_table.5.html">cidr</a>: 6686 # Rules are evaluated in the order as specified. 6687 # Blacklist 192.168.* except 192.168.0.1. 6688 192.168.0.1 dunno 6689 192.168.0.0/16 reject 6690</pre> 6691 6692<p> This feature is available in Postfix 2.8. </p> 6693 6694 6695</DD> 6696 6697<DT><b><a name="postscreen_bare_newline_action">postscreen_bare_newline_action</a> 6698(default: ignore)</b></DT><DD> 6699 6700<p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client sends 6701a bare newline character, that is, a newline not preceded by carriage 6702return. Specify one of the following: </p> 6703 6704<dl> 6705 6706<dt> <b>ignore</b> </dt> 6707 6708<dd> Ignore the failure of this test. Allow other tests to complete. 6709Do <i>not</i> repeat this test before some the result from some 6710other test expires. 6711This option is useful for testing and collecting statistics 6712without blocking mail permanently. </dd> 6713 6714<dt> <b>enforce</b> </dt> 6715 6716<dd> Allow other tests to complete. Reject attempts to deliver mail 6717with a 550 SMTP reply, and log the helo/sender/recipient information. 6718Repeat this test the next time the client connects. </dd> 6719 6720<dt> <b>drop</b> </dt> 6721 6722<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 6723this test the next time the client connects. </dd> 6724 6725</dl> 6726 6727<p> This feature is available in Postfix 2.8. </p> 6728 6729 6730</DD> 6731 6732<DT><b><a name="postscreen_bare_newline_enable">postscreen_bare_newline_enable</a> 6733(default: no)</b></DT><DD> 6734 6735<p> Enable "bare newline" SMTP protocol tests in the <a href="postscreen.8.html">postscreen(8)</a> 6736server. These tests are expensive: a client must disconnect after 6737it passes the test, before it can talk to a real Postfix SMTP server. 6738</p> 6739 6740<p> This feature is available in Postfix 2.8. </p> 6741 6742 6743</DD> 6744 6745<DT><b><a name="postscreen_bare_newline_ttl">postscreen_bare_newline_ttl</a> 6746(default: 30d)</b></DT><DD> 6747 6748<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will use the result from 6749a successful "bare newline" SMTP protocol test. During this 6750time, the client IP address is excluded from this test. The default 6751is long because a client must disconnect after it passes the test, 6752before it can talk to a real Postfix SMTP server. </p> 6753 6754<p> Specify a non-zero time value (an integral value plus an optional 6755one-letter suffix that specifies the time unit). Time units: s 6756(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 6757 6758<p> This feature is available in Postfix 2.8. </p> 6759 6760 6761</DD> 6762 6763<DT><b><a name="postscreen_blacklist_action">postscreen_blacklist_action</a> 6764(default: ignore)</b></DT><DD> 6765 6766<p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client is 6767permanently blacklisted with the <a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> parameter. 6768Specify one of the following: </p> 6769 6770<dl> 6771 6772<dt> <b>ignore</b> (default) </dt> 6773 6774<dd> Ignore this result. Allow other tests to complete. Repeat 6775this test the next time the client connects. 6776This option is useful for testing and collecting statistics 6777without blocking mail. </dd> 6778 6779<dt> <b>enforce</b> </dt> 6780 6781<dd> Allow other tests to complete. Reject attempts to deliver mail 6782with a 550 SMTP reply, and log the helo/sender/recipient information. 6783Repeat this test the next time the client connects. </dd> 6784 6785<dt> <b>drop</b> </dt> 6786 6787<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 6788this test the next time the client connects. </dd> 6789 6790</dl> 6791 6792<p> This feature is available in Postfix 2.8. </p> 6793 6794 6795</DD> 6796 6797<DT><b><a name="postscreen_cache_cleanup_interval">postscreen_cache_cleanup_interval</a> 6798(default: 12h)</b></DT><DD> 6799 6800<p> The amount of time between <a href="postscreen.8.html">postscreen(8)</a> cache cleanup runs. 6801Cache cleanup increases the load on the cache database and should 6802therefore not be run frequently. This feature requires that the 6803cache database supports the "delete" and "sequence" operators. 6804Specify a zero interval to disable cache cleanup. </p> 6805 6806<p> After each cache cleanup run, the <a href="postscreen.8.html">postscreen(8)</a> daemon logs the 6807number of entries that were retained and dropped. A cleanup run is 6808logged as "partial" when the daemon terminates early after "<b>postfix 6809reload</b>", "<b>postfix stop</b>", or no requests for $<a href="postconf.5.html#max_idle">max_idle</a> 6810seconds. </p> 6811 6812<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 6813(weeks). </p> 6814 6815<p> This feature is available in Postfix 2.8. </p> 6816 6817 6818</DD> 6819 6820<DT><b><a name="postscreen_cache_map">postscreen_cache_map</a> 6821(default: btree:$<a href="postconf.5.html#data_directory">data_directory</a>/postscreen_cache)</b></DT><DD> 6822 6823<p> Persistent storage for the <a href="postscreen.8.html">postscreen(8)</a> server decisions. </p> 6824 6825<p> This feature is available in Postfix 2.8. </p> 6826 6827 6828</DD> 6829 6830<DT><b><a name="postscreen_cache_retention_time">postscreen_cache_retention_time</a> 6831(default: 7d)</b></DT><DD> 6832 6833<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will cache an expired 6834temporary whitelist entry before it is removed. This prevents clients 6835from being logged as "NEW" just because their cache entry expired 6836an hour ago. It also prevents the cache from filling up with clients 6837that passed some deep protocol test once and never came back. </p> 6838 6839<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 6840(weeks). </p> 6841 6842<p> This feature is available in Postfix 2.8. </p> 6843 6844 6845</DD> 6846 6847<DT><b><a name="postscreen_client_connection_count_limit">postscreen_client_connection_count_limit</a> 6848(default: $<a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a>)</b></DT><DD> 6849 6850<p> How many simultaneous connections any client is allowed to have 6851with the <a href="postscreen.8.html">postscreen(8)</a> daemon. By default, this limit is the same 6852as with the Postfix SMTP server. Note that the triage process can 6853take several seconds, with the time spent in <a href="postconf.5.html#postscreen_greet_wait">postscreen_greet_wait</a> 6854delay, and with the time spent talking to the <a href="postscreen.8.html">postscreen(8)</a> built-in 6855dummy SMTP protocol engine. </p> 6856 6857<p> This feature is available in Postfix 2.8. </p> 6858 6859 6860</DD> 6861 6862<DT><b><a name="postscreen_command_count_limit">postscreen_command_count_limit</a> 6863(default: 20)</b></DT><DD> 6864 6865<p> The limit on the total number of commands per SMTP session for 6866<a href="postscreen.8.html">postscreen(8)</a>'s built-in SMTP protocol engine. This SMTP engine 6867defers or rejects all attempts to deliver mail, therefore there is 6868no need to enforce separate limits on the number of junk commands 6869and error commands. </p> 6870 6871<p> This feature is available in Postfix 2.8. </p> 6872 6873 6874</DD> 6875 6876<DT><b><a name="postscreen_command_filter">postscreen_command_filter</a> 6877(default: $<a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a>)</b></DT><DD> 6878 6879<p> A mechanism to transform commands from remote SMTP clients. 6880See <a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a> for further details. </p> 6881 6882<p> This feature is available in Postfix 2.8 and later. </p> 6883 6884 6885</DD> 6886 6887<DT><b><a name="postscreen_command_time_limit">postscreen_command_time_limit</a> 6888(default: ${stress?10}${stress:300}s)</b></DT><DD> 6889 6890<p> The time limit to read an entire command line with <a href="postscreen.8.html">postscreen(8)</a>'s 6891built-in SMTP protocol engine. </p> 6892 6893<p> This feature is available in Postfix 2.8. </p> 6894 6895 6896</DD> 6897 6898<DT><b><a name="postscreen_disable_vrfy_command">postscreen_disable_vrfy_command</a> 6899(default: $<a href="postconf.5.html#disable_vrfy_command">disable_vrfy_command</a>)</b></DT><DD> 6900 6901<p> Disable the SMTP VRFY command in the <a href="postscreen.8.html">postscreen(8)</a> daemon. See 6902<a href="postconf.5.html#disable_vrfy_command">disable_vrfy_command</a> for details. </p> 6903 6904<p> This feature is available in Postfix 2.8. </p> 6905 6906 6907</DD> 6908 6909<DT><b><a name="postscreen_discard_ehlo_keyword_address_maps">postscreen_discard_ehlo_keyword_address_maps</a> 6910(default: $<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_discard_ehlo_keyword_address_maps</a>)</b></DT><DD> 6911 6912<p> Lookup tables, indexed by the remote SMTP client address, with 6913case insensitive lists of EHLO keywords (pipelining, starttls, auth, 6914etc.) that the <a href="postscreen.8.html">postscreen(8)</a> server will not send in the EHLO response 6915to a remote SMTP client. See <a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_keywords</a> for details. 6916The table is not searched by hostname for robustness reasons. </p> 6917 6918<p> This feature is available in Postfix 2.8 and later. </p> 6919 6920 6921</DD> 6922 6923<DT><b><a name="postscreen_discard_ehlo_keywords">postscreen_discard_ehlo_keywords</a> 6924(default: $<a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_keywords</a>)</b></DT><DD> 6925 6926<p> A case insensitive list of EHLO keywords (pipelining, starttls, 6927auth, etc.) that the <a href="postscreen.8.html">postscreen(8)</a> server will not send in the EHLO 6928response to a remote SMTP client. See <a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_keywords</a> 6929for details. </p> 6930 6931<p> This feature is available in Postfix 2.8 and later. </p> 6932 6933 6934</DD> 6935 6936<DT><b><a name="postscreen_dnsbl_action">postscreen_dnsbl_action</a> 6937(default: ignore)</b></DT><DD> 6938 6939<p>The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client's combined 6940DNSBL score is equal to or greater than a threshold (as defined 6941with the <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> and <a href="postconf.5.html#postscreen_dnsbl_threshold">postscreen_dnsbl_threshold</a> 6942parameters). Specify one of the following: </p> 6943 6944<dl> 6945 6946<dt> <b>ignore</b> (default) </dt> 6947 6948<dd> Ignore the failure of this test. Allow other tests to complete. 6949Repeat this test the next time the client connects. 6950This option is useful for testing and collecting statistics 6951without blocking mail. </dd> 6952 6953<dt> <b>enforce</b> </dt> 6954 6955<dd> Allow other tests to complete. Reject attempts to deliver mail 6956with a 550 SMTP reply, and log the helo/sender/recipient information. 6957Repeat this test the next time the client connects. </dd> 6958 6959<dt> <b>drop</b> </dt> 6960 6961<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 6962this test the next time the client connects. </dd> 6963 6964</dl> 6965 6966<p> This feature is available in Postfix 2.8. </p> 6967 6968 6969</DD> 6970 6971<DT><b><a name="postscreen_dnsbl_reply_map">postscreen_dnsbl_reply_map</a> 6972(default: empty)</b></DT><DD> 6973 6974<p> A mapping from actual DNSBL domain name which includes a secret 6975password, to the DNSBL domain name that postscreen will reply with 6976when it rejects mail. When no mapping is found, the actual DNSBL 6977domain will be used. </p> 6978 6979<p> For maximal stability it is best to use a file that is read 6980into memory such as <a href="pcre_table.5.html">pcre</a>:, <a href="regexp_table.5.html">regexp</a>: or texthash: (texthash: is similar 6981to hash:, except a) there is no need to run <a href="postmap.1.html">postmap(1)</a> before the 6982file can be used, and b) texthash: does not detect changes after 6983the file is read). </p> 6984 6985<p> Example: </p> 6986 6987<pre> 6988/etc/postfix/<a href="postconf.5.html">main.cf</a>: 6989 <a href="postconf.5.html#postscreen_dnsbl_reply_map">postscreen_dnsbl_reply_map</a> = texthash:/etc/postfix/dnsbl_reply 6990</pre> 6991 6992<pre> 6993/etc/postfix/dnsbl_reply: 6994 secret.zen.spamhaus.org zen.spamhaus.org 6995</pre> 6996 6997<p> This feature is available in Postfix 2.8. </p> 6998 6999 7000</DD> 7001 7002<DT><b><a name="postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> 7003(default: empty)</b></DT><DD> 7004 7005<p>Optional list of DNS white/blacklist domains, filters and weight 7006factors. When the list is non-empty, the <a href="dnsblog.8.html">dnsblog(8)</a> daemon will 7007query these domains with the IP addresses of remote SMTP clients, 7008and <a href="postscreen.8.html">postscreen(8)</a> will update an SMTP client's DNSBL score with 7009each non-error reply. </p> 7010 7011<p> Caution: when postscreen rejects mail, it replies with the DNSBL 7012domain name. Use the <a href="postconf.5.html#postscreen_dnsbl_reply_map">postscreen_dnsbl_reply_map</a> feature to hide 7013"password" information in DNSBL domain names. </p> 7014 7015<p> When a client's score is equal to or greater than the threshold 7016specified with <a href="postconf.5.html#postscreen_dnsbl_threshold">postscreen_dnsbl_threshold</a>, <a href="postscreen.8.html">postscreen(8)</a> can drop 7017the connection with the SMTP client. </p> 7018 7019<p> Specify a list of domain=filter*weight entries, separated by 7020comma or whitespace. </p> 7021 7022<ul> 7023 7024<li> <p> When no "=filter" is specified, <a href="postscreen.8.html">postscreen(8)</a> will use any 7025non-error DNSBL reply. Otherwise, <a href="postscreen.8.html">postscreen(8)</a> uses only DNSBL 7026replies that match the filter. The filter has the form d.d.d.d, 7027where each d is a number, or a pattern inside [] that contains one 7028or more ";"-separated numbers or number..number ranges. </p> 7029 7030<li> <p> When no "*weight" is specified, <a href="postscreen.8.html">postscreen(8)</a> increments 7031the SMTP client's DNSBL score by 1. Otherwise, the weight must be 7032an integral number, and <a href="postscreen.8.html">postscreen(8)</a> adds the specified weight to 7033the SMTP client's DNSBL score. Specify a negative number for 7034whitelisting. </p> 7035 7036<li> <p> When one <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> entry produces multiple 7037DNSBL responses, <a href="postscreen.8.html">postscreen(8)</a> applies the weight at most once. 7038</p> 7039 7040</ul> 7041 7042<p> Examples: </p> 7043 7044<p> To use example.com as a high-confidence blocklist, and to 7045block mail with example.net and example.org only when both agree: 7046</p> 7047 7048<pre> 7049<a href="postconf.5.html#postscreen_dnsbl_threshold">postscreen_dnsbl_threshold</a> = 2 7050<a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> = example.com*2, example.net, example.org 7051</pre> 7052 7053<p> To filter only DNSBL replies containing 127.0.0.4: </p> 7054 7055<pre> 7056<a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> = example.com=127.0.0.4 7057</pre> 7058 7059<p> This feature is available in Postfix 2.8. </p> 7060 7061 7062</DD> 7063 7064<DT><b><a name="postscreen_dnsbl_threshold">postscreen_dnsbl_threshold</a> 7065(default: 1)</b></DT><DD> 7066 7067<p> The inclusive lower bound for blocking an SMTP client, based on 7068its combined DNSBL score as defined with the <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> 7069parameter. </p> 7070 7071<p> This feature is available in Postfix 2.8. </p> 7072 7073 7074</DD> 7075 7076<DT><b><a name="postscreen_dnsbl_ttl">postscreen_dnsbl_ttl</a> 7077(default: 1h)</b></DT><DD> 7078 7079<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will use the result from 7080a successful DNS blocklist test. During this time, the client IP address 7081is excluded from this test. The default is relatively short, because a 7082good client can immediately talk to a real Postfix SMTP server. 7083</p> 7084 7085<p> Specify a non-zero time value (an integral value plus an optional 7086one-letter suffix that specifies the time unit). Time units: s 7087(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 7088 7089<p> This feature is available in Postfix 2.8. </p> 7090 7091 7092</DD> 7093 7094<DT><b><a name="postscreen_enforce_tls">postscreen_enforce_tls</a> 7095(default: $<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b></DT><DD> 7096 7097<p> Mandatory TLS: announce STARTTLS support to SMTP clients, and 7098require that clients use TLS encryption. See smtpd_postscreen_enforce_tls 7099for details. </p> 7100 7101<p> This feature is available in Postfix 2.8 and later. 7102Preferably, use <a href="postconf.5.html#postscreen_tls_security_level">postscreen_tls_security_level</a> instead. </p> 7103 7104 7105</DD> 7106 7107<DT><b><a name="postscreen_expansion_filter">postscreen_expansion_filter</a> 7108(default: see "postconf -d" output)</b></DT><DD> 7109 7110<p> List of characters that are permitted in <a href="postconf.5.html#postscreen_reject_footer">postscreen_reject_footer</a> 7111attribute expansions. See <a href="postconf.5.html#smtpd_expansion_filter">smtpd_expansion_filter</a> for further 7112details. </p> 7113 7114<p> This feature is available in Postfix 2.8 and later. </p> 7115 7116 7117</DD> 7118 7119<DT><b><a name="postscreen_forbidden_commands">postscreen_forbidden_commands</a> 7120(default: $<a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a>)</b></DT><DD> 7121 7122<p> List of commands that the <a href="postscreen.8.html">postscreen(8)</a> server considers in 7123violation of the SMTP protocol. See <a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a> for 7124syntax, and <a href="postconf.5.html#postscreen_non_smtp_command_action">postscreen_non_smtp_command_action</a> for possible actions. 7125</p> 7126 7127<p> This feature is available in Postfix 2.8. </p> 7128 7129 7130</DD> 7131 7132<DT><b><a name="postscreen_greet_action">postscreen_greet_action</a> 7133(default: ignore)</b></DT><DD> 7134 7135<p>The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client speaks 7136before its turn within the time specified with the <a href="postconf.5.html#postscreen_greet_wait">postscreen_greet_wait</a> 7137parameter. Specify one of the following: </p> 7138 7139<dl> 7140 7141<dt> <b>ignore</b> (default) </dt> 7142 7143<dd> Ignore the failure of this test. Allow other tests to complete. 7144Repeat this test the next time the client connects. 7145This option is useful for testing and collecting statistics 7146without blocking mail. </dd> 7147 7148<dt> <b>enforce</b> </dt> 7149 7150<dd> Allow other tests to complete. Reject attempts to deliver mail 7151with a 550 SMTP reply, and log the helo/sender/recipient information. 7152Repeat this test the next time the client connects. </dd> 7153 7154<dt> <b>drop</b> </dt> 7155 7156<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 7157this test the next time the client connects. </dd> 7158 7159</dl> 7160 7161<p> In either case, <a href="postscreen.8.html">postscreen(8)</a> will not whitelist the SMTP client 7162IP address. </p> 7163 7164<p> This feature is available in Postfix 2.8. </p> 7165 7166 7167</DD> 7168 7169<DT><b><a name="postscreen_greet_banner">postscreen_greet_banner</a> 7170(default: $<a href="postconf.5.html#smtpd_banner">smtpd_banner</a>)</b></DT><DD> 7171 7172<p> The <i>text</i> in the optional "220-<i>text</i>..." server 7173response that 7174<a href="postscreen.8.html">postscreen(8)</a> sends ahead of the real Postfix SMTP server's "220 7175text..." response, in an attempt to confuse bad SMTP clients so 7176that they speak before their turn (pre-greet). Specify an empty 7177value to disable this feature. </p> 7178 7179<p> This feature is available in Postfix 2.8. </p> 7180 7181 7182</DD> 7183 7184<DT><b><a name="postscreen_greet_ttl">postscreen_greet_ttl</a> 7185(default: 1d)</b></DT><DD> 7186 7187<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will use the result from 7188a successful PREGREET test. During this time, the client IP address 7189is excluded from this test. The default is relatively short, because 7190a good client can immediately talk to a real Postfix SMTP server. </p> 7191 7192<p> Specify a non-zero time value (an integral value plus an optional 7193one-letter suffix that specifies the time unit). Time units: s 7194(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 7195 7196<p> This feature is available in Postfix 2.8. </p> 7197 7198 7199</DD> 7200 7201<DT><b><a name="postscreen_greet_wait">postscreen_greet_wait</a> 7202(default: ${stress?2}${stress:6}s)</b></DT><DD> 7203 7204<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will wait for an SMTP 7205client to send a command before its turn, and for DNS blocklist 7206lookup results to arrive (default: up to 2 seconds under stress, 7207up to 6 seconds otherwise). <p> 7208 7209<p> Specify a non-zero time value (an integral value plus an optional 7210one-letter suffix that specifies the time unit). </p> 7211 7212<p> Time units: s (seconds), m (minutes), h (hours), d (days), w 7213(weeks). </p> 7214 7215<p> This feature is available in Postfix 2.8. </p> 7216 7217 7218</DD> 7219 7220<DT><b><a name="postscreen_helo_required">postscreen_helo_required</a> 7221(default: $<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a>)</b></DT><DD> 7222 7223<p> Require that a remote SMTP client sends HELO or EHLO before 7224commencing a MAIL transaction. </p> 7225 7226<p> This feature is available in Postfix 2.8. </p> 7227 7228 7229</DD> 7230 7231<DT><b><a name="postscreen_non_smtp_command_action">postscreen_non_smtp_command_action</a> 7232(default: drop)</b></DT><DD> 7233 7234<p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client sends 7235non-SMTP commands as specified with the <a href="postconf.5.html#postscreen_forbidden_commands">postscreen_forbidden_commands</a> 7236parameter. Specify one of the following: </p> 7237 7238<dl> 7239 7240<dt> <b>ignore</b> </dt> 7241 7242<dd> Ignore the failure of this test. Allow other tests to complete. 7243Do <i>not</i> repeat this test before some the result from some 7244other test expires. 7245This option is useful for testing and collecting statistics 7246without blocking mail permanently. </dd> 7247 7248<dt> <b>enforce</b> </dt> 7249 7250<dd> Allow other tests to complete. Reject attempts to deliver mail 7251with a 550 SMTP reply, and log the helo/sender/recipient information. 7252Repeat this test the next time the client connects. </dd> 7253 7254<dt> <b>drop</b> </dt> 7255 7256<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 7257this test the next time the client connects. This action is the 7258same as with the Postfix SMTP server's <a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a> 7259feature. </dd> 7260 7261</dl> 7262 7263<p> This feature is available in Postfix 2.8. </p> 7264 7265 7266</DD> 7267 7268<DT><b><a name="postscreen_non_smtp_command_enable">postscreen_non_smtp_command_enable</a> 7269(default: no)</b></DT><DD> 7270 7271<p> Enable "non-SMTP command" tests in the <a href="postscreen.8.html">postscreen(8)</a> server. These 7272tests are expensive: a client must disconnect after it passes the 7273test, before it can talk to a real Postfix SMTP server. </p> 7274 7275<p> This feature is available in Postfix 2.8. </p> 7276 7277 7278</DD> 7279 7280<DT><b><a name="postscreen_non_smtp_command_ttl">postscreen_non_smtp_command_ttl</a> 7281(default: 30d)</b></DT><DD> 7282 7283<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will use the result from 7284a successful "non_smtp_command" SMTP protocol test. During this 7285time, the client IP address is excluded from this test. The default 7286is long because a client must disconnect after it passes the test, 7287before it can talk to a real Postfix SMTP server. </p> 7288 7289<p> Specify a non-zero time value (an integral value plus an optional 7290one-letter suffix that specifies the time unit). Time units: s 7291(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 7292 7293<p> This feature is available in Postfix 2.8. </p> 7294 7295 7296</DD> 7297 7298<DT><b><a name="postscreen_pipelining_action">postscreen_pipelining_action</a> 7299(default: enforce)</b></DT><DD> 7300 7301<p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client sends 7302multiple commands instead of sending one command and waiting for 7303the server to respond. Specify one of the following: </p> 7304 7305<dl> 7306 7307<dt> <b>ignore</b> </dt> 7308 7309<dd> Ignore the failure of this test. Allow other tests to complete. 7310Do <i>not</i> repeat this test before some the result from some 7311other test expires. 7312This option is useful for testing and collecting statistics 7313without blocking mail permanently. </dd> 7314 7315<dt> <b>enforce</b> </dt> 7316 7317<dd> Allow other tests to complete. Reject attempts to deliver mail 7318with a 550 SMTP reply, and log the helo/sender/recipient information. 7319Repeat this test the next time the client connects. </dd> 7320 7321<dt> <b>drop</b> </dt> 7322 7323<dd> Drop the connection immediately with a 521 SMTP reply. Repeat 7324this test the next time the client connects. </dd> 7325 7326</dl> 7327 7328<p> This feature is available in Postfix 2.8. </p> 7329 7330 7331</DD> 7332 7333<DT><b><a name="postscreen_pipelining_enable">postscreen_pipelining_enable</a> 7334(default: no)</b></DT><DD> 7335 7336<p> Enable "pipelining" SMTP protocol tests in the <a href="postscreen.8.html">postscreen(8)</a> 7337server. These tests are expensive: a good client must disconnect 7338after it passes the test, before it can talk to a real Postfix SMTP 7339server. </p> 7340 7341<p> This feature is available in Postfix 2.8. </p> 7342 7343 7344</DD> 7345 7346<DT><b><a name="postscreen_pipelining_ttl">postscreen_pipelining_ttl</a> 7347(default: 30d)</b></DT><DD> 7348 7349<p> The amount of time that <a href="postscreen.8.html">postscreen(8)</a> will use the result from 7350a successful "pipelining" SMTP protocol test. During this time, the 7351client IP address is excluded from this test. The default is 7352long because a good client must disconnect after it passes the test, 7353before it can talk to a real Postfix SMTP server. </p> 7354 7355<p> Specify a non-zero time value (an integral value plus an optional 7356one-letter suffix that specifies the time unit). Time units: s 7357(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 7358 7359<p> This feature is available in Postfix 2.8. </p> 7360 7361 7362</DD> 7363 7364<DT><b><a name="postscreen_post_queue_limit">postscreen_post_queue_limit</a> 7365(default: $<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b></DT><DD> 7366 7367<p> The number of clients that can be waiting for service from a 7368real SMTP server process. When this queue is full, all clients will 7369receive a 421 reponse. </p> 7370 7371<p> This feature is available in Postfix 2.8. </p> 7372 7373 7374</DD> 7375 7376<DT><b><a name="postscreen_pre_queue_limit">postscreen_pre_queue_limit</a> 7377(default: $<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b></DT><DD> 7378 7379<p> The number of non-whitelisted clients that can be waiting for 7380a decision whether they will receive service from a real SMTP server 7381process. When this queue is full, all non-whitelisted clients will 7382receive a 421 reponse. </p> 7383 7384<p> This feature is available in Postfix 2.8. </p> 7385 7386 7387</DD> 7388 7389<DT><b><a name="postscreen_reject_footer">postscreen_reject_footer</a> 7390(default: $<a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a>)</b></DT><DD> 7391 7392<p> Optional information that is appended after a 4XX or 5XX server 7393response. See <a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a> for further details. </p> 7394 7395<p> This feature is available in Postfix 2.8 and later. </p> 7396 7397 7398</DD> 7399 7400<DT><b><a name="postscreen_tls_security_level">postscreen_tls_security_level</a> 7401(default: $<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b></DT><DD> 7402 7403<p> The SMTP TLS security level for the <a href="postscreen.8.html">postscreen(8)</a> server; when 7404a non-empty value is specified, this overrides the obsolete parameters 7405<a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> and <a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a>. See <a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> 7406for details. </p> 7407 7408<p> This feature is available in Postfix 2.8 and later. </p> 7409 7410 7411</DD> 7412 7413<DT><b><a name="postscreen_use_tls">postscreen_use_tls</a> 7414(default: $<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b></DT><DD> 7415 7416<p> Opportunistic TLS: announce STARTTLS support to SMTP clients, 7417but do not require that clients use TLS encryption. </p> 7418 7419<p> This feature is available in Postfix 2.8 and later. 7420Preferably, use <a href="postconf.5.html#postscreen_tls_security_level">postscreen_tls_security_level</a> instead. </p> 7421 7422 7423</DD> 7424 7425<DT><b><a name="postscreen_watchdog_timeout">postscreen_watchdog_timeout</a> 7426(default: 10s)</b></DT><DD> 7427 7428<p> How much time a <a href="postscreen.8.html">postscreen(8)</a> process may take to respond to 7429an SMTP client command or to perform a cache operation before it 7430is terminated by a built-in watchdog timer. This is a safety 7431mechanism that prevents <a href="postscreen.8.html">postscreen(8)</a> from becoming non-responsive 7432due to a bug in Postfix itself or in system software. To avoid 7433false alarms and unnecessary cache corruption this limit cannot be 7434set under 10s. </p> 7435 7436<p> Specify a non-zero time value (an integral value plus an optional 7437one-letter suffix that specifies the time unit). Time units: s 7438(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 7439 7440<p> This feature is available in Postfix 2.8. </p> 7441 7442 7443</DD> 7444 7445<DT><b><a name="prepend_delivered_header">prepend_delivered_header</a> 7446(default: command, file, forward)</b></DT><DD> 7447 7448<p> The message delivery contexts where the Postfix <a href="local.8.html">local(8)</a> delivery 7449agent prepends a Delivered-To: message header with the address 7450that the mail was delivered to. This information is used for mail 7451delivery loop detection. </p> 7452 7453<p> 7454By default, the Postfix local delivery agent prepends a Delivered-To: 7455header when forwarding mail and when delivering to file (mailbox) 7456and command. Turning off the Delivered-To: header when forwarding 7457mail is not recommended. 7458</p> 7459 7460<p> 7461Specify zero or more of <b>forward</b>, <b>file</b>, or <b>command</b>. 7462</p> 7463 7464<p> 7465Example: 7466</p> 7467 7468<pre> 7469<a href="postconf.5.html#prepend_delivered_header">prepend_delivered_header</a> = forward 7470</pre> 7471 7472 7473</DD> 7474 7475<DT><b><a name="process_id">process_id</a> 7476(read-only)</b></DT><DD> 7477 7478<p> 7479The process ID of a Postfix command or daemon process. 7480</p> 7481 7482 7483</DD> 7484 7485<DT><b><a name="process_id_directory">process_id_directory</a> 7486(default: pid)</b></DT><DD> 7487 7488<p> 7489The location of Postfix PID files relative to $<a href="postconf.5.html#queue_directory">queue_directory</a>. 7490This is a read-only parameter. 7491</p> 7492 7493 7494</DD> 7495 7496<DT><b><a name="process_name">process_name</a> 7497(read-only)</b></DT><DD> 7498 7499<p> 7500The process name of a Postfix command or daemon process. 7501</p> 7502 7503 7504</DD> 7505 7506<DT><b><a name="propagate_unmatched_extensions">propagate_unmatched_extensions</a> 7507(default: canonical, virtual)</b></DT><DD> 7508 7509<p> 7510What address lookup tables copy an address extension from the lookup 7511key to the lookup result. 7512</p> 7513 7514<p> 7515For example, with a <a href="virtual.5.html">virtual(5)</a> mapping of "<i>joe@example.com => 7516joe.user@example.net</i>", the address "<i>joe+foo@example.com</i>" 7517would rewrite to "<i>joe.user+foo@example.net</i>". 7518</p> 7519 7520<p> 7521Specify zero or more of <b>canonical</b>, <b>virtual</b>, <b>alias</b>, 7522<b>forward</b>, <b>include</b> or <b>generic</b>. These cause 7523address extension 7524propagation with <a href="canonical.5.html">canonical(5)</a>, <a href="virtual.5.html">virtual(5)</a>, and <a href="aliases.5.html">aliases(5)</a> maps, 7525with <a href="local.8.html">local(8)</a> .forward and :include: file lookups, and with <a href="smtp.8.html">smtp(8)</a> 7526generic maps, respectively. </p> 7527 7528<p> 7529Note: enabling this feature for types other than <b>canonical</b> 7530and <b>virtual</b> is likely to cause problems when mail is forwarded 7531to other sites, especially with mail that is sent to a mailing list 7532exploder address. 7533</p> 7534 7535<p> 7536Examples: 7537</p> 7538 7539<pre> 7540<a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a> = canonical, virtual, alias, 7541 forward, include 7542<a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a> = canonical, virtual 7543</pre> 7544 7545 7546</DD> 7547 7548<DT><b><a name="proxy_interfaces">proxy_interfaces</a> 7549(default: empty)</b></DT><DD> 7550 7551<p> 7552The network interface addresses that this mail system receives mail 7553on by way of a proxy or network address translation unit. 7554</p> 7555 7556<p> 7557This feature is available in Postfix 2.0 and later. 7558</p> 7559 7560<p> You must specify your "outside" proxy/NAT addresses when your 7561system is a backup MX host for other domains, otherwise mail delivery 7562loops will happen when the primary MX host is down. </p> 7563 7564<p> 7565Example: 7566</p> 7567 7568<pre> 7569<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> = 1.2.3.4 7570</pre> 7571 7572 7573</DD> 7574 7575<DT><b><a name="proxy_read_maps">proxy_read_maps</a> 7576(default: see "postconf -d" output)</b></DT><DD> 7577 7578<p> 7579The lookup tables that the <a href="proxymap.8.html">proxymap(8)</a> server is allowed to 7580access for the read-only service. 7581Table references that don't begin with <a href="proxymap.8.html">proxy</a>: are ignored. 7582</p> 7583 7584<p> 7585This feature is available in Postfix 2.0 and later. 7586</p> 7587 7588 7589</DD> 7590 7591<DT><b><a name="proxy_write_maps">proxy_write_maps</a> 7592(default: see "postconf -d" output)</b></DT><DD> 7593 7594<p> The lookup tables that the <a href="proxymap.8.html">proxymap(8)</a> server is allowed to 7595access for the read-write service. Postfix-owned local database 7596files should be stored under the Postfix-owned <a href="postconf.5.html#data_directory">data_directory</a>. 7597Table references that don't begin with <a href="proxymap.8.html">proxy</a>: are ignored. </p> 7598 7599<p> 7600This feature is available in Postfix 2.5 and later. 7601</p> 7602 7603 7604</DD> 7605 7606<DT><b><a name="proxymap_service_name">proxymap_service_name</a> 7607(default: proxymap)</b></DT><DD> 7608 7609<p> The name of the proxymap read-only table lookup service. This 7610service is normally implemented by the <a href="proxymap.8.html">proxymap(8)</a> daemon. </p> 7611 7612<p> This feature is available in Postfix 2.6 and later. </p> 7613 7614 7615</DD> 7616 7617<DT><b><a name="proxywrite_service_name">proxywrite_service_name</a> 7618(default: proxywrite)</b></DT><DD> 7619 7620<p> The name of the proxywrite read-write table lookup service. 7621This service is normally implemented by the <a href="proxymap.8.html">proxymap(8)</a> daemon. 7622</p> 7623 7624<p> This feature is available in Postfix 2.6 and later. </p> 7625 7626 7627</DD> 7628 7629<DT><b><a name="qmgr_clog_warn_time">qmgr_clog_warn_time</a> 7630(default: 300s)</b></DT><DD> 7631 7632<p> 7633The minimal delay between warnings that a specific destination is 7634clogging up the Postfix <a href="QSHAPE_README.html#active_queue">active queue</a>. Specify 0 to disable. 7635</p> 7636 7637<p> 7638This feature is enabled with the <a href="postconf.5.html#helpful_warnings">helpful_warnings</a> parameter. 7639</p> 7640 7641<p> 7642This feature is available in Postfix 2.0 and later. 7643</p> 7644 7645 7646</DD> 7647 7648<DT><b><a name="qmgr_daemon_timeout">qmgr_daemon_timeout</a> 7649(default: 1000s)</b></DT><DD> 7650 7651<p> How much time a Postfix queue manager process may take to handle 7652a request before it is terminated by a built-in watchdog timer. 7653</p> 7654 7655<p> 7656Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 7657The default time unit is s (seconds). 7658</p> 7659 7660<p> This feature is available in Postfix 2.8 and later. </p> 7661 7662 7663</DD> 7664 7665<DT><b><a name="qmgr_fudge_factor">qmgr_fudge_factor</a> 7666(default: 100)</b></DT><DD> 7667 7668<p> 7669Obsolete feature: the percentage of delivery resources that a busy 7670mail system will use up for delivery of a large mailing list 7671message. 7672</p> 7673 7674<p> 7675This feature exists only in the <a href="qmgr.8.html">oqmgr(8)</a> old queue manager. The 7676current queue manager solves the problem in a better way. 7677</p> 7678 7679 7680</DD> 7681 7682<DT><b><a name="qmgr_ipc_timeout">qmgr_ipc_timeout</a> 7683(default: 60s)</b></DT><DD> 7684 7685<p> The time limit for the queue manager to send or receive information 7686over an internal communication channel. The purpose is to break 7687out of deadlock situations. If the time limit is exceeded the 7688software either retries or aborts the operation. </p> 7689 7690<p> 7691Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 7692The default time unit is s (seconds). 7693</p> 7694 7695<p> This feature is available in Postfix 2.8 and later. </p> 7696 7697 7698</DD> 7699 7700<DT><b><a name="qmgr_message_active_limit">qmgr_message_active_limit</a> 7701(default: 20000)</b></DT><DD> 7702 7703<p> 7704The maximal number of messages in the <a href="QSHAPE_README.html#active_queue">active queue</a>. 7705</p> 7706 7707 7708</DD> 7709 7710<DT><b><a name="qmgr_message_recipient_limit">qmgr_message_recipient_limit</a> 7711(default: 20000)</b></DT><DD> 7712 7713<p> The maximal number of recipients held in memory by the Postfix 7714queue manager, and the maximal size of the size of the short-term, 7715in-memory "dead" destination status cache. </p> 7716 7717 7718</DD> 7719 7720<DT><b><a name="qmgr_message_recipient_minimum">qmgr_message_recipient_minimum</a> 7721(default: 10)</b></DT><DD> 7722 7723<p> 7724The minimal number of in-memory recipients for any message. This 7725takes priority over any other in-memory recipient limits (i.e., 7726the global <a href="postconf.5.html#qmgr_message_recipient_limit">qmgr_message_recipient_limit</a> and the per transport 7727_recipient_limit) if necessary. The minimum value allowed for this 7728parameter is 1. 7729</p> 7730 7731 7732</DD> 7733 7734<DT><b><a name="qmqpd_authorized_clients">qmqpd_authorized_clients</a> 7735(default: empty)</b></DT><DD> 7736 7737<p> 7738What clients are allowed to connect to the QMQP server port. 7739</p> 7740 7741<p> 7742By default, no client is allowed to use the service. This is 7743because the QMQP server will relay mail to any destination. 7744</p> 7745 7746<p> 7747Specify a list of client patterns. A list pattern specifies a host 7748name, a domain name, an internet address, or a network/mask pattern, 7749where the mask specifies the number of bits in the network part. 7750When a pattern specifies a file name, its contents are substituted 7751for the file name; when a pattern is a "<a href="DATABASE_README.html">type:table</a>" table specification, 7752table lookup is used instead. </p> 7753 7754<p> 7755Patterns are separated by whitespace and/or commas. In order to 7756reverse the result, precede a pattern with an 7757exclamation point (!). The form "!/file/name" is supported only 7758in Postfix version 2.4 and later. 7759</p> 7760 7761<p> 7762Example: 7763</p> 7764 7765<pre> 7766<a href="postconf.5.html#qmqpd_authorized_clients">qmqpd_authorized_clients</a> = !192.168.0.1, 192.168.0.0/24 7767</pre> 7768 7769 7770</DD> 7771 7772<DT><b><a name="qmqpd_client_port_logging">qmqpd_client_port_logging</a> 7773(default: no)</b></DT><DD> 7774 7775<p> Enable logging of the remote QMQP client port in addition to 7776the hostname and IP address. The logging format is "host[address]:port". 7777</p> 7778 7779<p> This feature is available in Postfix 2.5 and later. </p> 7780 7781 7782</DD> 7783 7784<DT><b><a name="qmqpd_error_delay">qmqpd_error_delay</a> 7785(default: 1s)</b></DT><DD> 7786 7787<p> 7788How long the QMQP server will pause before sending a negative reply 7789to the client. The purpose is to slow down confused or malicious 7790clients. 7791</p> 7792 7793<p> 7794Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 7795The default time unit is s (seconds). 7796</p> 7797 7798 7799</DD> 7800 7801<DT><b><a name="qmqpd_timeout">qmqpd_timeout</a> 7802(default: 300s)</b></DT><DD> 7803 7804<p> 7805The time limit for sending or receiving information over the network. 7806If a read or write operation blocks for more than $<a href="postconf.5.html#qmqpd_timeout">qmqpd_timeout</a> 7807seconds the QMQP server gives up and disconnects. 7808</p> 7809 7810<p> 7811Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 7812The default time unit is s (seconds). 7813</p> 7814 7815 7816</DD> 7817 7818<DT><b><a name="queue_directory">queue_directory</a> 7819(default: see "postconf -d" output)</b></DT><DD> 7820 7821<p> 7822The location of the Postfix top-level queue directory. This is the 7823root directory of Postfix daemon processes that run chrooted. 7824</p> 7825 7826 7827</DD> 7828 7829<DT><b><a name="queue_file_attribute_count_limit">queue_file_attribute_count_limit</a> 7830(default: 100)</b></DT><DD> 7831 7832<p> 7833The maximal number of (name=value) attributes that may be stored 7834in a Postfix queue file. The limit is enforced by the <a href="cleanup.8.html">cleanup(8)</a> 7835server. 7836</p> 7837 7838<p> 7839This feature is available in Postfix 2.0 and later. 7840</p> 7841 7842 7843</DD> 7844 7845<DT><b><a name="queue_minfree">queue_minfree</a> 7846(default: 0)</b></DT><DD> 7847 7848<p> 7849The minimal amount of free space in bytes in the queue file system 7850that is needed to receive mail. This is currently used by the SMTP 7851server to decide if it will accept any mail at all. 7852</p> 7853 7854<p> 7855By default, the Postfix SMTP server rejects MAIL FROM commands when 7856the amount of free space is less than 1.5*$<a href="postconf.5.html#message_size_limit">message_size_limit</a> 7857(Postfix version 2.1 and later). 7858To specify a higher minimum free space limit, specify a <a href="postconf.5.html#queue_minfree">queue_minfree</a> 7859value that is at least 1.5*$<a href="postconf.5.html#message_size_limit">message_size_limit</a>. 7860</p> 7861 7862<p> 7863With Postfix versions 2.0 and earlier, a <a href="postconf.5.html#queue_minfree">queue_minfree</a> value of 7864zero means there is no minimum required amount of free space. 7865</p> 7866 7867 7868</DD> 7869 7870<DT><b><a name="queue_run_delay">queue_run_delay</a> 7871(default: 300s)</b></DT><DD> 7872 7873<p> 7874The time between <a href="QSHAPE_README.html#deferred_queue">deferred queue</a> scans by the queue manager; 7875prior to Postfix 2.4 the default value was 1000s. 7876</p> 7877 7878<p> This parameter should be set less than or equal to 7879$<a href="postconf.5.html#minimal_backoff_time">minimal_backoff_time</a>. See also $<a href="postconf.5.html#maximal_backoff_time">maximal_backoff_time</a>. </p> 7880 7881<p> 7882Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 7883The default time unit is s (seconds). 7884</p> 7885 7886 7887</DD> 7888 7889<DT><b><a name="queue_service_name">queue_service_name</a> 7890(default: qmgr)</b></DT><DD> 7891 7892<p> 7893The name of the <a href="qmgr.8.html">qmgr(8)</a> service. This service manages the Postfix 7894queue and schedules delivery requests. 7895</p> 7896 7897<p> 7898This feature is available in Postfix 2.0 and later. 7899</p> 7900 7901 7902</DD> 7903 7904<DT><b><a name="rbl_reply_maps">rbl_reply_maps</a> 7905(default: empty)</b></DT><DD> 7906 7907<p> 7908Optional lookup tables with RBL response templates. The tables are 7909indexed by the RBL domain name. By default, Postfix uses the default 7910template as specified with the <a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> configuration 7911parameter. See there for a discussion of the syntax of RBL reply 7912templates. 7913</p> 7914 7915<p> 7916This feature is available in Postfix 2.0 and later. 7917</p> 7918 7919 7920</DD> 7921 7922<DT><b><a name="readme_directory">readme_directory</a> 7923(default: see "postconf -d" output)</b></DT><DD> 7924 7925<p> 7926The location of Postfix README files that describe how to build, 7927configure or operate a specific Postfix subsystem or feature. 7928</p> 7929 7930 7931</DD> 7932 7933<DT><b><a name="receive_override_options">receive_override_options</a> 7934(default: empty)</b></DT><DD> 7935 7936<p> Enable or disable recipient validation, built-in content 7937filtering, or address mapping. Typically, these are specified in 7938<a href="master.5.html">master.cf</a> as command-line arguments for the <a href="smtpd.8.html">smtpd(8)</a>, <a href="qmqpd.8.html">qmqpd(8)</a> or 7939<a href="pickup.8.html">pickup(8)</a> daemons. </p> 7940 7941<p> Specify zero or more of the following options. The options 7942override <a href="postconf.5.html">main.cf</a> settings and are either implemented by <a href="smtpd.8.html">smtpd(8)</a>, 7943<a href="qmqpd.8.html">qmqpd(8)</a>, or <a href="pickup.8.html">pickup(8)</a> themselves, or they are forwarded to the 7944cleanup server. </p> 7945 7946<dl> 7947 7948<dt><b><a name="no_unknown_recipient_checks">no_unknown_recipient_checks</a></b></dt> 7949 7950<dd>Do not try to reject unknown recipients (SMTP server only). 7951This is typically specified AFTER an external content filter. 7952</dd> 7953 7954<dt><b><a name="no_address_mappings">no_address_mappings</a></b></dt> 7955 7956<dd>Disable canonical address mapping, virtual alias map expansion, 7957address masquerading, and automatic BCC (blind carbon-copy) 7958recipients. This is typically specified BEFORE an external content 7959filter. </dd> 7960 7961<dt><b><a name="no_header_body_checks">no_header_body_checks</a></b></dt> 7962 7963<dd>Disable header/body_checks. This is typically specified AFTER 7964an external content filter. </dd> 7965 7966<dt><b><a name="no_milters">no_milters</a></b></dt> 7967 7968<dd>Disable Milter (mail filter) applications. This is typically 7969specified AFTER an external content filter. </dd> 7970 7971</dl> 7972 7973<p> 7974Note: when the "BEFORE content filter" <a href="postconf.5.html#receive_override_options">receive_override_options</a> 7975setting is specified in the <a href="postconf.5.html">main.cf</a> file, specify the "AFTER content 7976filter" <a href="postconf.5.html#receive_override_options">receive_override_options</a> setting in <a href="master.5.html">master.cf</a> (and vice 7977versa). 7978</p> 7979 7980<p> 7981Examples: 7982</p> 7983 7984<pre> 7985<a href="postconf.5.html#receive_override_options">receive_override_options</a> = 7986 <a href="postconf.5.html#no_unknown_recipient_checks">no_unknown_recipient_checks</a>, <a href="postconf.5.html#no_header_body_checks">no_header_body_checks</a> 7987<a href="postconf.5.html#receive_override_options">receive_override_options</a> = <a href="postconf.5.html#no_address_mappings">no_address_mappings</a> 7988</pre> 7989 7990<p> 7991This feature is available in Postfix 2.1 and later. 7992</p> 7993 7994 7995</DD> 7996 7997<DT><b><a name="recipient_bcc_maps">recipient_bcc_maps</a> 7998(default: empty)</b></DT><DD> 7999 8000<p> 8001Optional BCC (blind carbon-copy) address lookup tables, indexed by 8002recipient address. The BCC address (multiple results are not 8003supported) is added when mail enters from outside of Postfix. 8004</p> 8005 8006<p> 8007This feature is available in Postfix 2.1 and later. 8008</p> 8009 8010<p> 8011The table search order is as follows: 8012</p> 8013 8014<ul> 8015 8016<li> Look up the "user+extension@domain.tld" address including the 8017optional address extension. 8018 8019<li> Look up the "user@domain.tld" address without the optional 8020address extension. 8021 8022<li> Look up the "user+extension" address local part when the 8023recipient domain equals $<a href="postconf.5.html#myorigin">myorigin</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 8024or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. 8025 8026<li> Look up the "user" address local part when the recipient domain 8027equals $<a href="postconf.5.html#myorigin">myorigin</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. 8028 8029<li> Look up the "@domain.tld" part. 8030 8031</ul> 8032 8033<p> 8034Specify the types and names of databases to use. After change, 8035run "<b>postmap /etc/postfix/recipient_bcc</b>". 8036</p> 8037 8038<p> 8039Note: if mail to the BCC address bounces it will be returned to 8040the sender. 8041</p> 8042 8043<p> Note: automatic BCC recipients are produced only for new mail. 8044To avoid mailer loops, automatic BCC recipients are not generated 8045after Postfix forwards mail internally, or after Postfix generates 8046mail itself. </p> 8047 8048<p> 8049Example: 8050</p> 8051 8052<pre> 8053<a href="postconf.5.html#recipient_bcc_maps">recipient_bcc_maps</a> = hash:/etc/postfix/recipient_bcc 8054</pre> 8055 8056 8057</DD> 8058 8059<DT><b><a name="recipient_canonical_classes">recipient_canonical_classes</a> 8060(default: envelope_recipient, header_recipient)</b></DT><DD> 8061 8062<p> What addresses are subject to <a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> address 8063mapping. By default, <a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> address mapping is 8064applied to envelope recipient addresses, and to header recipient 8065addresses. </p> 8066 8067<p> Specify one or more of: envelope_recipient, header_recipient 8068</p> 8069 8070<p> This feature is available in Postfix 2.2 and later. </p> 8071 8072 8073</DD> 8074 8075<DT><b><a name="recipient_canonical_maps">recipient_canonical_maps</a> 8076(default: empty)</b></DT><DD> 8077 8078<p> 8079Optional address mapping lookup tables for envelope and header 8080recipient addresses. 8081The table format and lookups are documented in <a href="canonical.5.html">canonical(5)</a>. 8082</p> 8083 8084<p> 8085Note: $<a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> is processed before $<a href="postconf.5.html#canonical_maps">canonical_maps</a>. 8086</p> 8087 8088<p> 8089Example: 8090</p> 8091 8092<pre> 8093<a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> = hash:/etc/postfix/recipient_canonical 8094</pre> 8095 8096 8097</DD> 8098 8099<DT><b><a name="recipient_delimiter">recipient_delimiter</a> 8100(default: empty)</b></DT><DD> 8101 8102<p> 8103The separator between user names and address extensions (user+foo). 8104See <a href="canonical.5.html">canonical(5)</a>, <a href="local.8.html">local(8)</a>, <a href="relocated.5.html">relocated(5)</a> and <a href="virtual.5.html">virtual(5)</a> for the 8105effects this has on aliases, canonical, virtual, relocated and 8106on .forward file lookups. Basically, the software tries user+foo 8107and .forward+foo before trying user and .forward. 8108</p> 8109 8110<p> 8111Example: 8112</p> 8113 8114<pre> 8115<a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> = + 8116</pre> 8117 8118 8119</DD> 8120 8121<DT><b><a name="reject_code">reject_code</a> 8122(default: 554)</b></DT><DD> 8123 8124<p> 8125The numerical Postfix SMTP server response code when a remote SMTP 8126client request is rejected by the "reject" restriction. 8127</p> 8128 8129<p> 8130Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 8131</p> 8132 8133 8134</DD> 8135 8136<DT><b><a name="reject_tempfail_action">reject_tempfail_action</a> 8137(default: <a href="postconf.5.html#defer_if_permit">defer_if_permit</a>)</b></DT><DD> 8138 8139<p> The Postfix SMTP server's action when a reject-type restriction 8140fails due to a temporary error condition. Specify "defer" to defer 8141the remote SMTP client request immediately. With the default 8142"<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" action, the Postfix SMTP server continues to look 8143for opportunities to reject mail, and defers the client request 8144only if it would otherwise be accepted. </p> 8145 8146<p> For finer control, see: <a href="postconf.5.html#unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a>, 8147<a href="postconf.5.html#unverified_sender_tempfail_action">unverified_sender_tempfail_action</a>, <a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a>, 8148and <a href="postconf.5.html#unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a>. </p> 8149 8150<p> This feature is available in Postfix 2.6 and later. </p> 8151 8152 8153</DD> 8154 8155<DT><b><a name="relay_clientcerts">relay_clientcerts</a> 8156(default: empty)</b></DT><DD> 8157 8158<p> List of tables with remote SMTP client-certificate fingerprints 8159for which the Postfix SMTP server will allow access with the 8160<a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a> feature. 8161The fingerprint digest algorithm is configurable via the 8162<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> parameter (hard-coded as md5 prior to 8163Postfix version 2.5). </p> 8164 8165<p> Postfix lookup tables are in the form of (key, value) pairs. 8166Since we only need the key, the value can be chosen freely, e.g. 8167the name of the user or host: 8168D7:04:2F:A7:0B:8C:A5:21:FA:31:77:E1:41:8A:EE:80 lutzpc.at.home </p> 8169 8170<p> Example: </p> 8171 8172<pre> 8173<a href="postconf.5.html#relay_clientcerts">relay_clientcerts</a> = hash:/etc/postfix/relay_clientcerts 8174</pre> 8175 8176<p>For more fine-grained control, use <a href="postconf.5.html#check_ccert_access">check_ccert_access</a> to select 8177an appropriate <a href="access.5.html">access(5)</a> policy for each client. 8178See <a href="RESTRICTION_CLASS_README.html">RESTRICTION_CLASS_README</a>.</p> 8179 8180<p>This feature is available with Postfix version 2.2.</p> 8181 8182 8183</DD> 8184 8185<DT><b><a name="relay_destination_concurrency_limit">relay_destination_concurrency_limit</a> 8186(default: $<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a>)</b></DT><DD> 8187 8188<p> The maximal number of parallel deliveries to the same destination 8189via the relay message delivery transport. This limit is enforced 8190by the queue manager. The message delivery transport name is the 8191first field in the entry in the <a href="master.5.html">master.cf</a> file. </p> 8192 8193<p> This feature is available in Postfix 2.0 and later. </p> 8194 8195 8196</DD> 8197 8198<DT><b><a name="relay_destination_recipient_limit">relay_destination_recipient_limit</a> 8199(default: $<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a>)</b></DT><DD> 8200 8201<p> The maximal number of recipients per message for the relay 8202message delivery transport. This limit is enforced by the queue 8203manager. The message delivery transport name is the first field in 8204the entry in the <a href="master.5.html">master.cf</a> file. </p> 8205 8206<p> Setting this parameter to a value of 1 changes the meaning of 8207<a href="postconf.5.html#relay_destination_concurrency_limit">relay_destination_concurrency_limit</a> from concurrency per domain 8208into concurrency per recipient. </p> 8209 8210<p> This feature is available in Postfix 2.0 and later. </p> 8211 8212 8213</DD> 8214 8215<DT><b><a name="relay_domains">relay_domains</a> 8216(default: $<a href="postconf.5.html#mydestination">mydestination</a>)</b></DT><DD> 8217 8218<p> What destination domains (and subdomains thereof) this system 8219will relay mail to. Subdomain matching is controlled with the 8220<a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> parameter. For details about how 8221the <a href="postconf.5.html#relay_domains">relay_domains</a> value is used, see the description of the 8222<a href="postconf.5.html#permit_auth_destination">permit_auth_destination</a> and <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> SMTP recipient 8223restrictions. </p> 8224 8225<p> Domains that match $<a href="postconf.5.html#relay_domains">relay_domains</a> are delivered with the 8226$<a href="postconf.5.html#relay_transport">relay_transport</a> mail delivery transport. The SMTP server validates 8227recipient addresses with $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> and rejects non-existent 8228recipients. See also the <a href="ADDRESS_CLASS_README.html#relay_domain_class">relay domains</a> address class in the 8229<a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> file. </p> 8230 8231<p> Note: Postfix will not automatically forward mail for domains 8232that list this system as their primary or backup MX host. See the 8233<a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> restriction in the <a href="postconf.5.html">postconf(5)</a> manual page. </p> 8234 8235<p> Specify a list of host or domain names, "/file/name" patterns 8236or "<a href="DATABASE_README.html">type:table</a>" lookup tables, separated by commas and/or whitespace. 8237Continue long lines by starting the next line with whitespace. A 8238"/file/name" pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" 8239lookup table is matched when a (parent) domain appears as lookup 8240key. Specify "!pattern" to exclude a domain from the list. The form 8241"!/file/name" is supported only in Postfix version 2.4 and later. 8242</p> 8243 8244 8245</DD> 8246 8247<DT><b><a name="relay_domains_reject_code">relay_domains_reject_code</a> 8248(default: 554)</b></DT><DD> 8249 8250<p> 8251The numerical Postfix SMTP server response code when a client 8252request is rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient 8253restriction. 8254</p> 8255 8256<p> 8257Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 8258</p> 8259 8260 8261</DD> 8262 8263<DT><b><a name="relay_recipient_maps">relay_recipient_maps</a> 8264(default: empty)</b></DT><DD> 8265 8266<p> Optional lookup tables with all valid addresses in the domains 8267that match $<a href="postconf.5.html#relay_domains">relay_domains</a>. Specify @domain as a wild-card for 8268domains that have no valid recipient list, and become a source of 8269backscatter mail: Postfix accepts spam for non-existent recipients 8270and then floods innocent people with undeliverable mail. Technically, 8271tables 8272listed with $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> are used as lists: Postfix needs 8273to know only if a lookup string is found or not, but it does not 8274use the result from table lookup. </p> 8275 8276<p> 8277If this parameter is non-empty, then the Postfix SMTP server will reject 8278mail to unknown relay users. This feature is off by default. 8279</p> 8280 8281<p> 8282See also the <a href="ADDRESS_CLASS_README.html#relay_domain_class">relay domains</a> address class in the <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> 8283file. 8284</p> 8285 8286<p> 8287Example: 8288</p> 8289 8290<pre> 8291<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> = hash:/etc/postfix/relay_recipients 8292</pre> 8293 8294<p> 8295This feature is available in Postfix 2.0 and later. 8296</p> 8297 8298 8299</DD> 8300 8301<DT><b><a name="relay_transport">relay_transport</a> 8302(default: relay)</b></DT><DD> 8303 8304<p> 8305The default mail delivery transport and next-hop destination for 8306remote delivery to domains listed with $<a href="postconf.5.html#relay_domains">relay_domains</a>. In order of 8307decreasing precedence, the nexthop destination is taken from 8308$<a href="postconf.5.html#relay_transport">relay_transport</a>, $<a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a>, $<a href="postconf.5.html#relayhost">relayhost</a>, or 8309from the recipient domain. This information can be overruled with 8310the <a href="transport.5.html">transport(5)</a> table. 8311</p> 8312 8313<p> 8314Specify a string of the form <i>transport:nexthop</i>, where <i>transport</i> 8315is the name of a mail delivery transport defined in <a href="master.5.html">master.cf</a>. 8316The <i>:nexthop</i> destination is optional; its syntax is documented 8317in the manual page of the corresponding delivery agent. 8318</p> 8319 8320<p> 8321See also the <a href="ADDRESS_CLASS_README.html#relay_domain_class">relay domains</a> address class in the <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> 8322file. 8323</p> 8324 8325<p> 8326This feature is available in Postfix 2.0 and later. 8327</p> 8328 8329 8330</DD> 8331 8332<DT><b><a name="relayhost">relayhost</a> 8333(default: empty)</b></DT><DD> 8334 8335<p> 8336The next-hop destination of non-local mail; overrides non-local 8337domains in recipient addresses. This information is overruled with 8338<a href="postconf.5.html#relay_transport">relay_transport</a>, <a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a>, 8339<a href="postconf.5.html#default_transport">default_transport</a>, <a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> 8340and with the <a href="transport.5.html">transport(5)</a> table. 8341</p> 8342 8343<p> 8344On an intranet, specify the organizational domain name. If your 8345internal DNS uses no MX records, specify the name of the intranet 8346gateway host instead. 8347</p> 8348 8349<p> 8350In the case of SMTP, specify a domain name, hostname, hostname:port, 8351[hostname]:port, [hostaddress] or [hostaddress]:port. The form 8352[hostname] turns off MX lookups. 8353</p> 8354 8355<p> 8356If you're connected via UUCP, see the <a href="UUCP_README.html">UUCP_README</a> file for useful 8357information. 8358</p> 8359 8360<p> 8361Examples: 8362</p> 8363 8364<pre> 8365<a href="postconf.5.html#relayhost">relayhost</a> = $<a href="postconf.5.html#mydomain">mydomain</a> 8366<a href="postconf.5.html#relayhost">relayhost</a> = [gateway.example.com] 8367<a href="postconf.5.html#relayhost">relayhost</a> = uucphost 8368<a href="postconf.5.html#relayhost">relayhost</a> = [an.ip.add.ress] 8369</pre> 8370 8371 8372</DD> 8373 8374<DT><b><a name="relocated_maps">relocated_maps</a> 8375(default: empty)</b></DT><DD> 8376 8377<p> 8378Optional lookup tables with new contact information for users or 8379domains that no longer exist. The table format and lookups are 8380documented in <a href="relocated.5.html">relocated(5)</a>. 8381</p> 8382 8383<p> 8384If you use this feature, run "<b>postmap /etc/postfix/relocated</b>" to 8385build the necessary DBM or DB file after change, then "<b>postfix 8386reload</b>" to make the changes visible. 8387</p> 8388 8389<p> 8390Examples: 8391</p> 8392 8393<pre> 8394<a href="postconf.5.html#relocated_maps">relocated_maps</a> = dbm:/etc/postfix/relocated 8395<a href="postconf.5.html#relocated_maps">relocated_maps</a> = hash:/etc/postfix/relocated 8396</pre> 8397 8398 8399</DD> 8400 8401<DT><b><a name="remote_header_rewrite_domain">remote_header_rewrite_domain</a> 8402(default: empty)</b></DT><DD> 8403 8404<p> Don't rewrite message headers from remote clients at all when 8405this parameter is empty; otherwise, rewrite message headers and 8406append the specified domain name to incomplete addresses. The 8407<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> parameter controls what clients Postfix 8408considers local. </p> 8409 8410<p> Examples: </p> 8411 8412<p> The safe setting: append "domain.invalid" to incomplete header 8413addresses from remote SMTP clients, so that those addresses cannot 8414be confused with local addresses. </p> 8415 8416<blockquote> 8417<pre> 8418<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> = domain.invalid 8419</pre> 8420</blockquote> 8421 8422<p> The default, purist, setting: don't rewrite headers from remote 8423clients at all. </p> 8424 8425<blockquote> 8426<pre> 8427<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> = 8428</pre> 8429</blockquote> 8430 8431 8432</DD> 8433 8434<DT><b><a name="require_home_directory">require_home_directory</a> 8435(default: no)</b></DT><DD> 8436 8437<p> 8438Require that a <a href="local.8.html">local(8)</a> recipient's home directory exists 8439before mail delivery is attempted. By default this test is disabled. 8440It can be useful for environments that import home directories to 8441the mail server (IMPORTING HOME DIRECTORIES IS NOT RECOMMENDED). 8442</p> 8443 8444 8445</DD> 8446 8447<DT><b><a name="reset_owner_alias">reset_owner_alias</a> 8448(default: no)</b></DT><DD> 8449 8450<p> Reset the <a href="local.8.html">local(8)</a> delivery agent's idea of the owner-alias 8451attribute, when delivering mail to a child alias that does not have 8452its own owner alias. </p> 8453 8454<p> This feature is available in Postfix 2.8 and later. With older 8455Postfix releases, the behavior is as if this parameter is set to 8456"yes". </p> 8457 8458<p> As documented in <a href="aliases.5.html">aliases(5)</a>, when an alias <i>name</i> has a 8459companion alias named owner-<i>name</i>, delivery errors will be 8460reported to the owner alias instead of the sender. This configuration 8461is recommended for mailing lists. <p> 8462 8463<p> A less known property of the owner alias is that it also forces 8464the <a href="local.8.html">local(8)</a> delivery agent to write local and remote addresses 8465from alias expansion to a new queue file, instead of attempting to 8466deliver mail to local addresses as soon as they come out of alias 8467expansion. </p> 8468 8469<p> Writing local addresses from alias expansion to a new queue 8470file allows for robust handling of temporary delivery errors: errors 8471with one local member have no effect on deliveries to other members 8472of the list. On the other hand, delivery to local addresses as 8473soon as they come out of alias expansion is fragile: a temporary 8474error with one local address from alias expansion will cause the 8475entire alias to be expanded repeatedly until the error goes away, 8476or until the message expires in the queue. In that case, a problem 8477with one list member results in multiple message deliveries to other 8478list members. </p> 8479 8480<p> The default behavior of Postfix 2.8 and later is to keep the 8481owner-alias attribute of the parent alias, when delivering mail to 8482a child alias that does not have its own owner alias. Then, local 8483addresses from that child alias will be written to a new queue file, 8484and a temporary error with one local address will not affect delivery 8485to other mailing list members. </p> 8486 8487<p> Unfortunately, older Postfix releases reset the owner-alias 8488attribute when delivering mail to a child alias that does not have 8489its own owner alias. The <a href="local.8.html">local(8)</a> delivery agent then attempts to 8490deliver local addresses as soon as they come out of child alias 8491expansion. If delivery to any address from child alias expansion 8492fails with a temporary error condition, the entire mailing list may 8493be expanded repeatedly until the mail expires in the queue, resulting 8494in multiple deliveries of the same message to mailing list members. 8495</p> 8496 8497 8498</DD> 8499 8500<DT><b><a name="resolve_dequoted_address">resolve_dequoted_address</a> 8501(default: yes)</b></DT><DD> 8502 8503<p> Resolve a recipient address safely instead of correctly, by 8504looking inside quotes. </p> 8505 8506<p> By default, the Postfix address resolver does not quote the 8507address localpart as per <a href="http://tools.ietf.org/html/rfc822">RFC 822</a>, so that additional @ or % or ! 8508operators remain visible. This behavior is safe but it is also 8509technically incorrect. </p> 8510 8511<p> If you specify "<a href="postconf.5.html#resolve_dequoted_address">resolve_dequoted_address</a> = no", then 8512the Postfix 8513resolver will not know about additional @ etc. operators in the 8514address localpart. This opens opportunities for obscure mail relay 8515attacks with user@domain@domain addresses when Postfix provides 8516backup MX service for Sendmail systems. </p> 8517 8518 8519</DD> 8520 8521<DT><b><a name="resolve_null_domain">resolve_null_domain</a> 8522(default: no)</b></DT><DD> 8523 8524<p> Resolve an address that ends in the "@" null domain as if the 8525local hostname were specified, instead of rejecting the address as 8526invalid. </p> 8527 8528<p> This feature is available in Postfix 2.1 and later. 8529Earlier versions always resolve the null domain as the local 8530hostname. </p> 8531 8532<p> The Postfix SMTP server uses this feature to reject mail from 8533or to addresses that end in the "@" null domain, and from addresses 8534that rewrite into a form that ends in the "@" null domain. </p> 8535 8536 8537</DD> 8538 8539<DT><b><a name="resolve_numeric_domain">resolve_numeric_domain</a> 8540(default: no)</b></DT><DD> 8541 8542<p> Resolve "user@ipaddress" as "user@[ipaddress]", instead of 8543rejecting the address as invalid. </p> 8544 8545<p> This feature is available in Postfix 2.3 and later. 8546 8547 8548</DD> 8549 8550<DT><b><a name="rewrite_service_name">rewrite_service_name</a> 8551(default: rewrite)</b></DT><DD> 8552 8553<p> 8554The name of the address rewriting service. This service rewrites 8555addresses to standard form and resolves them to a (delivery method, 8556next-hop host, recipient) triple. 8557</p> 8558 8559<p> 8560This feature is available in Postfix 2.0 and later. 8561</p> 8562 8563 8564</DD> 8565 8566<DT><b><a name="sample_directory">sample_directory</a> 8567(default: /etc/postfix)</b></DT><DD> 8568 8569<p> 8570The name of the directory with example Postfix configuration files. 8571Starting with Postfix 2.1, these files have been replaced with the 8572<a href="postconf.5.html">postconf(5)</a> manual page. 8573</p> 8574 8575 8576</DD> 8577 8578<DT><b><a name="send_cyrus_sasl_authzid">send_cyrus_sasl_authzid</a> 8579(default: no)</b></DT><DD> 8580 8581<p> When authenticating to a remote SMTP or LMTP server with the 8582default setting "no", send no SASL authoriZation ID (authzid); send 8583only the SASL authentiCation ID (authcid) plus the authcid's password. 8584</p> 8585 8586<p> The non-default setting "yes" enables the behavior of older 8587Postfix versions. These always send a SASL authzid that is equal 8588to the SASL authcid, but this causes inter-operability problems 8589with some SMTP servers. </p> 8590 8591<p> This feature is available in Postfix 2.4.4 and later. </p> 8592 8593 8594</DD> 8595 8596<DT><b><a name="sender_based_routing">sender_based_routing</a> 8597(default: no)</b></DT><DD> 8598 8599<p> 8600This parameter should not be used. It was replaced by <a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> 8601in Postfix version 2.3. 8602</p> 8603 8604 8605</DD> 8606 8607<DT><b><a name="sender_bcc_maps">sender_bcc_maps</a> 8608(default: empty)</b></DT><DD> 8609 8610<p> Optional BCC (blind carbon-copy) address lookup tables, indexed 8611by sender address. The BCC address (multiple results are not 8612supported) is added when mail enters from outside of Postfix. </p> 8613 8614<p> 8615This feature is available in Postfix 2.1 and later. 8616</p> 8617 8618<p> 8619The table search order is as follows: 8620</p> 8621 8622<ul> 8623 8624<li> Look up the "user+extension@domain.tld" address including the 8625optional address extension. 8626 8627<li> Look up the "user@domain.tld" address without the optional 8628address extension. 8629 8630<li> Look up the "user+extension" address local part when the 8631sender domain equals $<a href="postconf.5.html#myorigin">myorigin</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 8632or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. 8633 8634<li> Look up the "user" address local part when the sender domain 8635equals $<a href="postconf.5.html#myorigin">myorigin</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. 8636 8637<li> Look up the "@domain.tld" part. 8638 8639</ul> 8640 8641<p> 8642Specify the types and names of databases to use. After change, 8643run "<b>postmap /etc/postfix/sender_bcc</b>". 8644</p> 8645 8646<p> 8647Note: if mail to the BCC address bounces it will be returned to 8648the sender. 8649</p> 8650 8651<p> Note: automatic BCC recipients are produced only for new mail. 8652To avoid mailer loops, automatic BCC recipients are not generated 8653after Postfix forwards mail internally, or after Postfix generates 8654mail itself. </p> 8655 8656<p> 8657Example: 8658</p> 8659 8660<pre> 8661<a href="postconf.5.html#sender_bcc_maps">sender_bcc_maps</a> = hash:/etc/postfix/sender_bcc 8662</pre> 8663 8664 8665</DD> 8666 8667<DT><b><a name="sender_canonical_classes">sender_canonical_classes</a> 8668(default: envelope_sender, header_sender)</b></DT><DD> 8669 8670<p> What addresses are subject to <a href="postconf.5.html#sender_canonical_maps">sender_canonical_maps</a> address 8671mapping. By default, <a href="postconf.5.html#sender_canonical_maps">sender_canonical_maps</a> address mapping is 8672applied to envelope sender addresses, and to header sender addresses. 8673</p> 8674 8675<p> Specify one or more of: envelope_sender, header_sender </p> 8676 8677<p> This feature is available in Postfix 2.2 and later. </p> 8678 8679 8680</DD> 8681 8682<DT><b><a name="sender_canonical_maps">sender_canonical_maps</a> 8683(default: empty)</b></DT><DD> 8684 8685<p> 8686Optional address mapping lookup tables for envelope and header 8687sender addresses. 8688The table format and lookups are documented in <a href="canonical.5.html">canonical(5)</a>. 8689</p> 8690 8691<p> 8692Example: you want to rewrite the SENDER address "user@ugly.domain" 8693to "user@pretty.domain", while still being able to send mail to 8694the RECIPIENT address "user@ugly.domain". 8695</p> 8696 8697<p> 8698Note: $<a href="postconf.5.html#sender_canonical_maps">sender_canonical_maps</a> is processed before $<a href="postconf.5.html#canonical_maps">canonical_maps</a>. 8699</p> 8700 8701<p> 8702Example: 8703</p> 8704 8705<pre> 8706<a href="postconf.5.html#sender_canonical_maps">sender_canonical_maps</a> = hash:/etc/postfix/sender_canonical 8707</pre> 8708 8709 8710</DD> 8711 8712<DT><b><a name="sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a> 8713(default: empty)</b></DT><DD> 8714 8715<p> A sender-dependent override for the global <a href="postconf.5.html#default_transport">default_transport</a> 8716parameter setting. The tables are searched by the envelope sender 8717address and @domain. A lookup result of DUNNO terminates the search 8718without overriding the global <a href="postconf.5.html#default_transport">default_transport</a> parameter setting. 8719This information is overruled with the <a href="transport.5.html">transport(5)</a> table. </p> 8720 8721<p> Note: this overrides <a href="postconf.5.html#default_transport">default_transport</a>, not <a href="postconf.5.html#transport_maps">transport_maps</a>, and 8722therefore the expected syntax is that of <a href="postconf.5.html#default_transport">default_transport</a>, not the 8723syntax of <a href="postconf.5.html#transport_maps">transport_maps</a>. Specifically, this does not support the 8724<a href="postconf.5.html#transport_maps">transport_maps</a> syntax for null transport, null nexthop, or null 8725email addresses. </p> 8726 8727<p> For safety reasons, this feature does not allow $number 8728substitutions in regular expression maps. </p> 8729 8730<p> This feature is available in Postfix 2.7 and later. </p> 8731 8732 8733</DD> 8734 8735<DT><b><a name="sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a> 8736(default: empty)</b></DT><DD> 8737 8738<p> A sender-dependent override for the global <a href="postconf.5.html#relayhost">relayhost</a> parameter 8739setting. The tables are searched by the envelope sender address and 8740@domain. A lookup result of DUNNO terminates the search without 8741overriding the global <a href="postconf.5.html#relayhost">relayhost</a> parameter setting (Postfix 2.6 and 8742later). This information is overruled with <a href="postconf.5.html#relay_transport">relay_transport</a>, 8743<a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a>, <a href="postconf.5.html#default_transport">default_transport</a> and with 8744the <a href="transport.5.html">transport(5)</a> table. </p> 8745 8746<p> For safety reasons, this feature does not allow $number 8747substitutions in regular expression maps. </p> 8748 8749<p> 8750This feature is available in Postfix 2.3 and later. 8751</p> 8752 8753 8754</DD> 8755 8756<DT><b><a name="sendmail_path">sendmail_path</a> 8757(default: see "postconf -d" output)</b></DT><DD> 8758 8759<p> 8760A Sendmail compatibility feature that specifies the location of 8761the Postfix <a href="sendmail.1.html">sendmail(1)</a> command. This command can be used to 8762submit mail into the Postfix queue. 8763</p> 8764 8765 8766</DD> 8767 8768<DT><b><a name="service_throttle_time">service_throttle_time</a> 8769(default: 60s)</b></DT><DD> 8770 8771<p> 8772How long the Postfix <a href="master.8.html">master(8)</a> waits before forking a server that 8773appears to be malfunctioning. 8774</p> 8775 8776<p> 8777Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 8778The default time unit is s (seconds). 8779</p> 8780 8781 8782</DD> 8783 8784<DT><b><a name="setgid_group">setgid_group</a> 8785(default: postdrop)</b></DT><DD> 8786 8787<p> 8788The group ownership of set-gid Postfix commands and of group-writable 8789Postfix directories. When this parameter value is changed you need 8790to re-run "<b>postfix set-permissions</b>" (with Postfix version 2.0 and 8791earlier: "<b>/etc/postfix/post-install set-permissions</b>". 8792</p> 8793 8794 8795</DD> 8796 8797<DT><b><a name="show_user_unknown_table_name">show_user_unknown_table_name</a> 8798(default: yes)</b></DT><DD> 8799 8800<p> 8801Display the name of the recipient table in the "User unknown" 8802responses. The extra detail makes trouble shooting easier but also 8803reveals information that is nobody elses business. 8804</p> 8805 8806<p> 8807This feature is available in Postfix 2.0 and later. 8808</p> 8809 8810 8811</DD> 8812 8813<DT><b><a name="showq_service_name">showq_service_name</a> 8814(default: showq)</b></DT><DD> 8815 8816<p> 8817The name of the <a href="showq.8.html">showq(8)</a> service. This service produces mail queue 8818status reports. 8819</p> 8820 8821<p> 8822This feature is available in Postfix 2.0 and later. 8823</p> 8824 8825 8826</DD> 8827 8828<DT><b><a name="smtp_address_preference">smtp_address_preference</a> 8829(default: ipv6)</b></DT><DD> 8830 8831<p> The address type ("ipv6", "ipv4" or "any") that the Postfix 8832SMTP client will try first, when a destination has IPv6 and IPv4 8833addresses with equal MX preference. This feature has no effect 8834unless the <a href="postconf.5.html#inet_protocols">inet_protocols</a> setting enables both IPv4 and IPv6. </p> 8835 8836<p> This feature is available in Postfix 2.8 and later. </p> 8837 8838 8839</DD> 8840 8841<DT><b><a name="smtp_always_send_ehlo">smtp_always_send_ehlo</a> 8842(default: yes)</b></DT><DD> 8843 8844<p> 8845Always send EHLO at the start of an SMTP session. 8846</p> 8847 8848<p> 8849With "<a href="postconf.5.html#smtp_always_send_ehlo">smtp_always_send_ehlo</a> = no", Postfix sends EHLO only when 8850the word "ESMTP" appears in the server greeting banner (example: 8851220 spike.porcupine.org ESMTP Postfix). 8852</p> 8853 8854 8855</DD> 8856 8857<DT><b><a name="smtp_bind_address">smtp_bind_address</a> 8858(default: empty)</b></DT><DD> 8859 8860<p> 8861An optional numerical network address that the Postfix SMTP client 8862should bind to when making an IPv4 connection. 8863</p> 8864 8865<p> 8866This can be specified in the <a href="postconf.5.html">main.cf</a> file for all SMTP clients, or 8867it can be specified in the <a href="master.5.html">master.cf</a> file for a specific client, 8868for example: 8869</p> 8870 8871<blockquote> 8872<pre> 8873/etc/postfix/<a href="master.5.html">master.cf</a>: 8874 smtp ... smtp -o <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a>=11.22.33.44 8875</pre> 8876</blockquote> 8877 8878<p> Note 1: when <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> specifies no more than one IPv4 8879address, and that address is a non-loopback address, it is 8880automatically used as the <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a>. This supports virtual 8881IP hosting, but can be a problem on multi-homed firewalls. See the 8882<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> documentation for more detail. </p> 8883 8884<p> Note 2: address information may be enclosed inside <tt>[]</tt>, 8885but this form is not required here. </p> 8886 8887 8888</DD> 8889 8890<DT><b><a name="smtp_bind_address6">smtp_bind_address6</a> 8891(default: empty)</b></DT><DD> 8892 8893<p> 8894An optional numerical network address that the Postfix SMTP client 8895should bind to when making an IPv6 connection. 8896</p> 8897 8898<p> This feature is available in Postfix 2.2 and later. </p> 8899 8900<p> 8901This can be specified in the <a href="postconf.5.html">main.cf</a> file for all SMTP clients, or 8902it can be specified in the <a href="master.5.html">master.cf</a> file for a specific client, 8903for example: 8904</p> 8905 8906<blockquote> 8907<pre> 8908/etc/postfix/<a href="master.5.html">master.cf</a>: 8909 smtp ... smtp -o <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a>=1:2:3:4:5:6:7:8 8910</pre> 8911</blockquote> 8912 8913<p> Note 1: when <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> specifies no more than one IPv6 8914address, and that address is a non-loopback address, it is 8915automatically used as the <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a>. This supports virtual 8916IP hosting, but can be a problem on multi-homed firewalls. See the 8917<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> documentation for more detail. </p> 8918 8919<p> Note 2: address information may be enclosed inside <tt>[]</tt>, 8920but this form is not recommended here. </p> 8921 8922 8923</DD> 8924 8925<DT><b><a name="smtp_body_checks">smtp_body_checks</a> 8926(default: empty)</b></DT><DD> 8927 8928<p> Restricted <a href="header_checks.5.html">body_checks(5)</a> tables for the Postfix SMTP client. 8929These tables are searched while mail is being delivered. Actions 8930that change the delivery time or destination are not available. 8931</p> 8932 8933<p> This feature is available in Postfix 2.5 and later. </p> 8934 8935 8936</DD> 8937 8938<DT><b><a name="smtp_cname_overrides_servername">smtp_cname_overrides_servername</a> 8939(default: version dependent)</b></DT><DD> 8940 8941<p> Allow DNS CNAME records to override the servername that the 8942Postfix SMTP client uses for logging, SASL password lookup, TLS 8943policy decisions, or TLS certificate verification. The value "no" 8944hardens Postfix <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> hostname-based policies against 8945false hostname information in DNS CNAME records, and makes SASL 8946password file lookups more predictable. This is the default setting 8947as of Postfix 2.3. </p> 8948 8949<p> This feature is available in Postfix 2.2.9 and later. </p> 8950 8951 8952</DD> 8953 8954<DT><b><a name="smtp_connect_timeout">smtp_connect_timeout</a> 8955(default: 30s)</b></DT><DD> 8956 8957<p> 8958The SMTP client time limit for completing a TCP connection, or 8959zero (use the operating system built-in time limit). 8960</p> 8961 8962<p> 8963When no connection can be made within the deadline, the Postfix 8964SMTP client 8965tries the next address on the mail exchanger list. Specify 0 to 8966disable the time limit (i.e. use whatever timeout is implemented by 8967the operating system). 8968</p> 8969 8970<p> 8971Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 8972The default time unit is s (seconds). 8973</p> 8974 8975 8976</DD> 8977 8978<DT><b><a name="smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> 8979(default: empty)</b></DT><DD> 8980 8981<p> Permanently enable SMTP connection caching for the specified 8982destinations. With SMTP connection caching, a connection is not 8983closed immediately after completion of a mail transaction. Instead, 8984the connection is kept open for up to $<a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> 8985seconds. This allows connections to be reused for other deliveries, 8986and can improve mail delivery performance. </p> 8987 8988<p> Specify a comma or white space separated list of destinations 8989or pseudo-destinations: </p> 8990 8991<ul> 8992 8993<li> if mail is sent without a <a href="postconf.5.html#relayhost">relay host</a>: a domain name (the 8994right-hand side of an email address, without the [] around a numeric 8995IP address), 8996 8997<li> if mail is sent via a <a href="postconf.5.html#relayhost">relay host</a>: a <a href="postconf.5.html#relayhost">relay host</a> name (without 8998[] or non-default TCP port), as specified in <a href="postconf.5.html">main.cf</a> or in the 8999transport map, 9000 9001<li> if mail is sent via a UNIX-domain socket: a pathname (without 9002the unix: prefix), 9003 9004<li> a /file/name with domain names and/or <a href="postconf.5.html#relayhost">relay host</a> names as 9005defined above, 9006 9007<li> a "<a href="DATABASE_README.html">type:table</a>" with domain names and/or <a href="postconf.5.html#relayhost">relay host</a> names on 9008the left-hand side. The right-hand side result from "<a href="DATABASE_README.html">type:table</a>" 9009lookups is ignored. 9010 9011</ul> 9012 9013<p> This feature is available in Postfix 2.2 and later. </p> 9014 9015 9016</DD> 9017 9018<DT><b><a name="smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> 9019(default: yes)</b></DT><DD> 9020 9021<p> Temporarily enable SMTP connection caching while a destination 9022has a high volume of mail in the <a href="QSHAPE_README.html#active_queue">active queue</a>. With SMTP connection 9023caching, a connection is not closed immediately after completion 9024of a mail transaction. Instead, the connection is kept open for 9025up to $<a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> seconds. This allows 9026connections to be reused for other deliveries, and can improve mail 9027delivery performance. </p> 9028 9029<p> This feature is available in Postfix 2.2 and later. </p> 9030 9031 9032</DD> 9033 9034<DT><b><a name="smtp_connection_cache_reuse_limit">smtp_connection_cache_reuse_limit</a> 9035(default: 10)</b></DT><DD> 9036 9037<p> When SMTP connection caching is enabled, the number of times that 9038an SMTP session may be reused before it is closed. 9039</p> 9040 9041<p> This feature is available in Postfix 2.2. In Postfix 2.3 it is 9042replaced by $<a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a>.</p> 9043 9044 9045</DD> 9046 9047<DT><b><a name="smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> 9048(default: 2s)</b></DT><DD> 9049 9050<p> When SMTP connection caching is enabled, the amount of time that 9051an unused SMTP client socket is kept open before it is closed. Do 9052not specify larger values without permission from the remote sites. 9053</p> 9054 9055<p> This feature is available in Postfix 2.2 and later. </p> 9056 9057 9058</DD> 9059 9060<DT><b><a name="smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> 9061(default: 300s)</b></DT><DD> 9062 9063<p> The amount of time during which Postfix will use an SMTP 9064connection repeatedly. The timer starts when the connection is 9065initiated (i.e. it includes the connect, greeting and helo latency, 9066in addition to the latencies of subsequent mail delivery transactions). 9067</p> 9068 9069<p> This feature addresses a performance stability problem with 9070remote SMTP servers. This problem is not specific to Postfix: it 9071can happen when any MTA sends large amounts of SMTP email to a site 9072that has multiple MX hosts. </p> 9073 9074<p> The problem starts when one of a set of MX hosts becomes slower 9075than the rest. Even though SMTP clients connect to fast and slow 9076MX hosts with equal probability, the slow MX host ends up with more 9077simultaneous inbound connections than the faster MX hosts, because 9078the slow MX host needs more time to serve each client request. </p> 9079 9080<p> The slow MX host becomes a connection attractor. If one MX 9081host becomes N times slower than the rest, it dominates mail delivery 9082latency unless there are more than N fast MX hosts to counter the 9083effect. And if the number of MX hosts is smaller than N, the mail 9084delivery latency becomes effectively that of the slowest MX host 9085divided by the total number of MX hosts. </p> 9086 9087<p> The solution uses connection caching in a way that differs from 9088Postfix version 2.2. By limiting the amount of time during which a connection 9089can be used repeatedly (instead of limiting the number of deliveries 9090over that connection), Postfix not only restores fairness in the 9091distribution of simultaneous connections across a set of MX hosts, 9092it also favors deliveries over connections that perform well, which 9093is exactly what we want. </p> 9094 9095<p> The default reuse time limit, 300s, is comparable to the various 9096smtp transaction timeouts which are fair estimates of maximum excess 9097latency for a slow delivery. Note that hosts may accept thousands 9098of messages over a single connection within the default connection 9099reuse time limit. This number is much larger than the default Postfix 9100version 2.2 limit of 10 messages per cached connection. It may prove necessary 9101to lower the limit to avoid interoperability issues with MTAs that 9102exhibit bugs when many messages are delivered via a single connection. 9103A lower reuse time limit risks losing the benefit of connection 9104reuse when the average connection and mail delivery latency exceeds 9105the reuse time limit. </p> 9106 9107<p> This feature is available in Postfix 2.3 and later. </p> 9108 9109 9110</DD> 9111 9112<DT><b><a name="smtp_data_done_timeout">smtp_data_done_timeout</a> 9113(default: 600s)</b></DT><DD> 9114 9115<p> 9116The SMTP client time limit for sending the SMTP ".", and for receiving 9117the server response. 9118</p> 9119 9120<p> 9121When no response is received within the deadline, a warning is 9122logged that the mail may be delivered multiple times. 9123</p> 9124 9125<p> 9126Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9127The default time unit is s (seconds). 9128</p> 9129 9130 9131</DD> 9132 9133<DT><b><a name="smtp_data_init_timeout">smtp_data_init_timeout</a> 9134(default: 120s)</b></DT><DD> 9135 9136<p> 9137The SMTP client time limit for sending the SMTP DATA command, and for 9138receiving the server response. 9139</p> 9140 9141<p> 9142Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9143The default time unit is s (seconds). 9144</p> 9145 9146 9147</DD> 9148 9149<DT><b><a name="smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> 9150(default: 180s)</b></DT><DD> 9151 9152<p> 9153The SMTP client time limit for sending the SMTP message content. 9154When the connection makes no progress for more than $<a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> 9155seconds the Postfix SMTP client terminates the transfer. 9156</p> 9157 9158<p> 9159Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9160The default time unit is s (seconds). 9161</p> 9162 9163 9164</DD> 9165 9166<DT><b><a name="smtp_defer_if_no_mx_address_found">smtp_defer_if_no_mx_address_found</a> 9167(default: no)</b></DT><DD> 9168 9169<p> 9170Defer mail delivery when no MX record resolves to an IP address. 9171</p> 9172 9173<p> 9174The default (no) is to return the mail as undeliverable. With older 9175Postfix versions the default was to keep trying to deliver the mail 9176until someone fixed the MX record or until the mail was too old. 9177</p> 9178 9179<p> 9180Note: Postfix always ignores MX records with equal or worse preference 9181than the local MTA itself. 9182</p> 9183 9184<p> 9185This feature is available in Postfix 2.1 and later. 9186</p> 9187 9188 9189</DD> 9190 9191<DT><b><a name="smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> 9192(default: $<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a>)</b></DT><DD> 9193 9194<p> The maximal number of parallel deliveries to the same destination 9195via the smtp message delivery transport. This limit is enforced by 9196the queue manager. The message delivery transport name is the first 9197field in the entry in the <a href="master.5.html">master.cf</a> file. </p> 9198 9199 9200</DD> 9201 9202<DT><b><a name="smtp_destination_recipient_limit">smtp_destination_recipient_limit</a> 9203(default: $<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a>)</b></DT><DD> 9204 9205<p> The maximal number of recipients per message for the smtp 9206message delivery transport. This limit is enforced by the queue 9207manager. The message delivery transport name is the first field in 9208the entry in the <a href="master.5.html">master.cf</a> file. </p> 9209 9210<p> Setting this parameter to a value of 1 changes the meaning of 9211<a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> from concurrency per domain 9212into concurrency per recipient. </p> 9213 9214 9215</DD> 9216 9217<DT><b><a name="smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a> 9218(default: empty)</b></DT><DD> 9219 9220<p> Lookup tables, indexed by the remote SMTP server address, with 9221case insensitive lists of EHLO keywords (pipelining, starttls, auth, 9222etc.) that the Postfix SMTP client will ignore in the EHLO response from a 9223remote SMTP server. See <a href="postconf.5.html#smtp_discard_ehlo_keywords">smtp_discard_ehlo_keywords</a> for details. The 9224table is not indexed by hostname for consistency with 9225<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_discard_ehlo_keyword_address_maps</a>. </p> 9226 9227<p> This feature is available in Postfix 2.2 and later. </p> 9228 9229 9230</DD> 9231 9232<DT><b><a name="smtp_discard_ehlo_keywords">smtp_discard_ehlo_keywords</a> 9233(default: empty)</b></DT><DD> 9234 9235<p> A case insensitive list of EHLO keywords (pipelining, starttls, 9236auth, etc.) that the Postfix SMTP client will ignore in the EHLO 9237response from a remote SMTP server. </p> 9238 9239<p> This feature is available in Postfix 2.2 and later. </p> 9240 9241<p> Notes: </p> 9242 9243<ul> 9244 9245<li> <p> Specify the <b>silent-discard</b> pseudo keyword to prevent 9246this action from being logged. </p> 9247 9248<li> <p> Use the <a href="postconf.5.html#smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a> feature to 9249discard EHLO keywords selectively. </p> 9250 9251</ul> 9252 9253 9254</DD> 9255 9256<DT><b><a name="smtp_dns_resolver_options">smtp_dns_resolver_options</a> 9257(default: empty)</b></DT><DD> 9258 9259<p> DNS Resolver options for the Postfix SMTP client. Specify zero 9260or more of the following options, separated by comma or whitespace. 9261Option names are case-sensitive. Some options refer to domain names 9262that are specified in the file /etc/resolv.conf or equivalent. </p> 9263 9264<dl> 9265 9266<dt><b>res_defnames</b></dt> 9267 9268<dd> Append the current domain name to single-component names (those 9269that do not contain a "." character). This can produce incorrect 9270results, and is the hard-coded behavior prior to Postfix 2.8. </dd> 9271 9272<dt><b>res_dnsrch</b></dt> 9273 9274<dd> Search for host names in the current domain and in parent 9275domains. This can produce incorrect results and is therefore not 9276recommended. </dd> 9277 9278</dl> 9279 9280<p> This feature is available in Postfix 2.8 and later. </p> 9281 9282 9283</DD> 9284 9285<DT><b><a name="smtp_enforce_tls">smtp_enforce_tls</a> 9286(default: no)</b></DT><DD> 9287 9288<p> Enforcement mode: require that remote SMTP servers use TLS 9289encryption, and never send mail in the clear. This also requires 9290that the remote SMTP server hostname matches the information in 9291the remote server certificate, and that the remote SMTP server 9292certificate was issued by a CA that is trusted by the Postfix SMTP 9293client. If the certificate doesn't verify or the hostname doesn't 9294match, delivery is deferred and mail stays in the queue. </p> 9295 9296<p> The server hostname is matched against all names provided as 9297dNSNames in the SubjectAlternativeName. If no dNSNames are specified, 9298the CommonName is checked. The behavior may be changed with the 9299<a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> option. </p> 9300 9301<p> This option is useful only if you are definitely sure that you 9302will only connect to servers that support <a href="http://tools.ietf.org/html/rfc2487">RFC 2487</a> _and_ that 9303provide valid server certificates. Typical use is for clients that 9304send all their email to a dedicated mailhub. </p> 9305 9306<p> This feature is available in Postfix 2.2 and later. With 9307Postfix 2.3 and later use <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> instead. </p> 9308 9309 9310</DD> 9311 9312<DT><b><a name="smtp_fallback_relay">smtp_fallback_relay</a> 9313(default: $<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b></DT><DD> 9314 9315<p> 9316Optional list of relay hosts for SMTP destinations that can't be 9317found or that are unreachable. With Postfix 2.2 and earlier this 9318parameter is called <a href="postconf.5.html#fallback_relay">fallback_relay</a>. </p> 9319 9320<p> 9321By default, mail is returned to the sender when a destination is 9322not found, and delivery is deferred when a destination is unreachable. 9323</p> 9324 9325<p> The fallback relays must be SMTP destinations. Specify a domain, 9326host, host:port, [host]:port, [address] or [address]:port; the form 9327[host] turns off MX lookups. If you specify multiple SMTP 9328destinations, Postfix will try them in the specified order. </p> 9329 9330<p> To prevent mailer loops between MX hosts and fall-back hosts, 9331Postfix version 2.2 and later will not use the fallback relays for 9332destinations that it is MX host for (assuming DNS lookup is turned on). 9333</p> 9334 9335 9336</DD> 9337 9338<DT><b><a name="smtp_generic_maps">smtp_generic_maps</a> 9339(default: empty)</b></DT><DD> 9340 9341<p> Optional lookup tables that perform address rewriting in the 9342SMTP client, typically to transform a locally valid address into 9343a globally valid address when sending mail across the Internet. 9344This is needed when the local machine does not have its own Internet 9345domain name, but uses something like <i>localdomain.local</i> 9346instead. </p> 9347 9348<p> The table format and lookups are documented in <a href="generic.5.html">generic(5)</a>; 9349examples are shown in the <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a> and 9350<a href="STANDARD_CONFIGURATION_README.html">STANDARD_CONFIGURATION_README</a> documents. </p> 9351 9352<p> This feature is available in Postfix 2.2 and later. </p> 9353 9354 9355</DD> 9356 9357<DT><b><a name="smtp_header_checks">smtp_header_checks</a> 9358(default: empty)</b></DT><DD> 9359 9360<p> Restricted <a href="header_checks.5.html">header_checks(5)</a> tables for the Postfix SMTP client. 9361These tables are searched while mail is being delivered. Actions 9362that change the delivery time or destination are not available. 9363</p> 9364 9365<p> This feature is available in Postfix 2.5 and later. </p> 9366 9367 9368</DD> 9369 9370<DT><b><a name="smtp_helo_name">smtp_helo_name</a> 9371(default: $<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 9372 9373<p> 9374The hostname to send in the SMTP EHLO or HELO command. 9375</p> 9376 9377<p> 9378The default value is the machine hostname. Specify a hostname or 9379[ip.add.re.ss]. 9380</p> 9381 9382<p> 9383This information can be specified in the <a href="postconf.5.html">main.cf</a> file for all SMTP 9384clients, or it can be specified in the <a href="master.5.html">master.cf</a> file for a specific 9385client, for example: 9386</p> 9387 9388<blockquote> 9389<pre> 9390/etc/postfix/<a href="master.5.html">master.cf</a>: 9391 mysmtp ... smtp -o <a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a>=foo.bar.com 9392</pre> 9393</blockquote> 9394 9395<p> 9396This feature is available in Postfix 2.0 and later. 9397</p> 9398 9399 9400</DD> 9401 9402<DT><b><a name="smtp_helo_timeout">smtp_helo_timeout</a> 9403(default: 300s)</b></DT><DD> 9404 9405<p> 9406The SMTP client time limit for sending the HELO or EHLO command, 9407and for receiving the initial server response. 9408</p> 9409 9410<p> 9411Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9412The default time unit is s (seconds). 9413</p> 9414 9415 9416</DD> 9417 9418<DT><b><a name="smtp_host_lookup">smtp_host_lookup</a> 9419(default: dns)</b></DT><DD> 9420 9421<p> 9422What mechanisms the Postfix SMTP client uses to look up a host's IP 9423address. This parameter is ignored when DNS lookups are disabled 9424(see: <a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a>). 9425</p> 9426 9427<p> 9428Specify one of the following: 9429</p> 9430 9431<dl> 9432 9433<dt><b>dns</b></dt> 9434 9435<dd>Hosts can be found in the DNS (preferred). </dd> 9436 9437<dt><b>native</b></dt> 9438 9439<dd>Use the native naming service only (nsswitch.conf, or equivalent 9440mechanism). </dd> 9441 9442<dt><b>dns, native</b></dt> 9443 9444<dd>Use the native service for hosts not found in the DNS. </dd> 9445 9446</dl> 9447 9448<p> 9449This feature is available in Postfix 2.1 and later. 9450</p> 9451 9452 9453</DD> 9454 9455<DT><b><a name="smtp_line_length_limit">smtp_line_length_limit</a> 9456(default: 990)</b></DT><DD> 9457 9458<p> 9459The maximal length of message header and body lines that Postfix 9460will send via SMTP. Longer lines are broken by inserting 9461"<CR><LF><SPACE>". This minimizes the damage to 9462MIME formatted mail. 9463</p> 9464 9465<p> 9466By default, the line length is limited to 990 characters, because 9467some server implementations cannot receive mail with long lines. 9468</p> 9469 9470 9471</DD> 9472 9473<DT><b><a name="smtp_mail_timeout">smtp_mail_timeout</a> 9474(default: 300s)</b></DT><DD> 9475 9476<p> 9477The SMTP client time limit for sending the MAIL FROM command, and 9478for receiving the server response. 9479</p> 9480 9481<p> 9482Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9483The default time unit is s (seconds). 9484</p> 9485 9486 9487</DD> 9488 9489<DT><b><a name="smtp_mime_header_checks">smtp_mime_header_checks</a> 9490(default: empty)</b></DT><DD> 9491 9492<p> Restricted mime_<a href="header_checks.5.html">header_checks(5)</a> tables for the Postfix SMTP 9493client. These tables are searched while mail is being delivered. 9494Actions that change the delivery time or destination are not 9495available. </p> 9496 9497<p> This feature is available in Postfix 2.5 and later. </p> 9498 9499 9500</DD> 9501 9502<DT><b><a name="smtp_mx_address_limit">smtp_mx_address_limit</a> 9503(default: 5)</b></DT><DD> 9504 9505<p> 9506The maximal number of MX (mail exchanger) IP addresses that can 9507result from mail exchanger lookups, or zero (no limit). Prior to 9508Postfix version 2.3, this limit was disabled by default. 9509</p> 9510 9511<p> 9512This feature is available in Postfix 2.1 and later. 9513</p> 9514 9515 9516</DD> 9517 9518<DT><b><a name="smtp_mx_session_limit">smtp_mx_session_limit</a> 9519(default: 2)</b></DT><DD> 9520 9521<p> The maximal number of SMTP sessions per delivery request before 9522giving up or delivering to a fall-back <a href="postconf.5.html#relayhost">relay host</a>, or zero (no 9523limit). This restriction ignores sessions that fail to complete the 9524SMTP initial handshake (Postfix version 2.2 and earlier) or that fail to 9525complete the EHLO and TLS handshake (Postfix version 2.3 and later). </p> 9526 9527<p> This feature is available in Postfix 2.1 and later. </p> 9528 9529 9530</DD> 9531 9532<DT><b><a name="smtp_nested_header_checks">smtp_nested_header_checks</a> 9533(default: empty)</b></DT><DD> 9534 9535<p> Restricted nested_<a href="header_checks.5.html">header_checks(5)</a> tables for the Postfix SMTP 9536client. These tables are searched while mail is being delivered. 9537Actions that change the delivery time or destination are not 9538available. </p> 9539 9540<p> This feature is available in Postfix 2.5 and later. </p> 9541 9542 9543</DD> 9544 9545<DT><b><a name="smtp_never_send_ehlo">smtp_never_send_ehlo</a> 9546(default: no)</b></DT><DD> 9547 9548<p> Never send EHLO at the start of an SMTP session. See also the 9549<a href="postconf.5.html#smtp_always_send_ehlo">smtp_always_send_ehlo</a> parameter. </p> 9550 9551 9552</DD> 9553 9554<DT><b><a name="smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> 9555(default: 10s)</b></DT><DD> 9556 9557<p> 9558How long the Postfix SMTP client pauses before sending 9559".<CR><LF>" in order to work around the PIX firewall 9560"<CR><LF>.<CR><LF>" bug. 9561</p> 9562 9563<p> 9564Choosing a too short time makes this workaround ineffective when 9565sending large messages over slow network connections. 9566</p> 9567 9568 9569</DD> 9570 9571<DT><b><a name="smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> 9572(default: empty)</b></DT><DD> 9573 9574<p> Lookup tables, indexed by the remote SMTP server address, with 9575per-destination workarounds for CISCO PIX firewall bugs. The table 9576is not indexed by hostname for consistency with 9577<a href="postconf.5.html#smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a>. </p> 9578 9579<p> This feature is available in Postfix 2.4 and later. </p> 9580 9581 9582</DD> 9583 9584<DT><b><a name="smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> 9585(default: 500s)</b></DT><DD> 9586 9587<p> How long a message must be queued before the Postfix SMTP client 9588turns on the PIX firewall "<CR><LF>.<CR><LF>" 9589bug workaround for delivery through firewalls with "smtp fixup" 9590mode turned on. </p> 9591 9592<p> 9593By default, the workaround is turned off for mail that is queued 9594for less than 500 seconds. In other words, the workaround is normally 9595turned off for the first delivery attempt. 9596</p> 9597 9598<p> 9599Specify 0 to enable the PIX firewall 9600"<CR><LF>.<CR><LF>" bug workaround upon the 9601first delivery attempt. 9602</p> 9603 9604 9605</DD> 9606 9607<DT><b><a name="smtp_pix_workarounds">smtp_pix_workarounds</a> 9608(default: disable_esmtp, delay_dotcrlf)</b></DT><DD> 9609 9610<p> A list that specifies zero or more workarounds for CISCO PIX 9611firewall bugs. These workarounds are implemented by the Postfix 9612SMTP client. Workaround names are separated by comma or space, and 9613are case insensitive. This parameter setting can be overruled with 9614per-destination <a href="postconf.5.html#smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> settings. </p> 9615 9616<dl> 9617 9618<dt><b>delay_dotcrlf</b><dd> Insert a delay before sending 9619".<CR><LF>" after the end of the message content. The 9620delay is subject to the <a href="postconf.5.html#smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> and 9621<a href="postconf.5.html#smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> parameter settings. </dd> 9622 9623<dt><b>disable_esmtp</b><dd> Disable all extended SMTP commands: 9624send HELO instead of EHLO. </dd> 9625 9626</dl> 9627 9628<p> This feature is available in Postfix 2.4 and later. The default 9629settings are backwards compatible with earlier Postfix versions. 9630</p> 9631 9632 9633</DD> 9634 9635<DT><b><a name="smtp_quit_timeout">smtp_quit_timeout</a> 9636(default: 300s)</b></DT><DD> 9637 9638<p> 9639The SMTP client time limit for sending the QUIT command, and for 9640receiving the server response. 9641</p> 9642 9643<p> 9644Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9645The default time unit is s (seconds). 9646</p> 9647 9648 9649</DD> 9650 9651<DT><b><a name="smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a> 9652(default: yes)</b></DT><DD> 9653 9654<p> 9655Quote addresses in SMTP MAIL FROM and RCPT TO commands as required 9656by <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. This includes putting quotes around an address localpart 9657that ends in ".". 9658</p> 9659 9660<p> 9661The default is to comply with <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. If you have to send mail to 9662a broken SMTP server, configure a special SMTP client in <a href="master.5.html">master.cf</a>: 9663</p> 9664 9665<blockquote> 9666<pre> 9667/etc/postfix/<a href="master.5.html">master.cf</a>: 9668 broken-smtp . . . smtp -o <a href="postconf.5.html#smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a>=no 9669</pre> 9670</blockquote> 9671 9672<p> 9673and route mail for the destination in question to the "broken-smtp" 9674message delivery with a <a href="transport.5.html">transport(5)</a> table. 9675</p> 9676 9677<p> 9678This feature is available in Postfix 2.1 and later. 9679</p> 9680 9681 9682</DD> 9683 9684<DT><b><a name="smtp_randomize_addresses">smtp_randomize_addresses</a> 9685(default: yes)</b></DT><DD> 9686 9687<p> 9688Randomize the order of equal-preference MX host addresses. This 9689is a performance feature of the Postfix SMTP client. 9690</p> 9691 9692 9693</DD> 9694 9695<DT><b><a name="smtp_rcpt_timeout">smtp_rcpt_timeout</a> 9696(default: 300s)</b></DT><DD> 9697 9698<p> 9699The SMTP client time limit for sending the SMTP RCPT TO command, and 9700for receiving the server response. 9701</p> 9702 9703<p> 9704Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 9705The default time unit is s (seconds). 9706</p> 9707 9708 9709</DD> 9710 9711<DT><b><a name="smtp_reply_filter">smtp_reply_filter</a> 9712(default: empty)</b></DT><DD> 9713 9714<p> A mechanism to transform replies from remote SMTP servers one 9715line at a time. This is a last-resort tool to work around server 9716replies that break inter-operability with the Postfix SMTP client. 9717Other uses involve fault injection to test Postfix's handling of 9718invalid responses. </p> 9719 9720<p> Notes: </p> 9721 9722<ul> 9723 9724<li> <p> In the case of a multi-line reply, the Postfix SMTP client 9725uses the final reply line's numerical SMTP reply code and enhanced 9726status code. </p> 9727 9728<li> <p> The numerical SMTP reply code (XYZ) takes precedence over 9729the enhanced status code (X.Y.Z). When the enhanced status code 9730initial digit differs from the SMTP reply code initial digit, or 9731when no enhanced status code is present, the Postfix SMTP client 9732uses a generic enhanced status code (X.0.0) instead. </p> 9733 9734</ul> 9735 9736<p> Specify the name of a "<a href="DATABASE_README.html">type:table</a>" lookup table. The search 9737string is a single SMTP reply line as received from the remote SMTP 9738server, except that the trailing <CR><LF> are removed. </p> 9739 9740<p> Examples: </p> 9741 9742<pre> 9743/etc/postfix/<a href="postconf.5.html">main.cf</a>: 9744 <a href="postconf.5.html#smtp_reply_filter">smtp_reply_filter</a> = <a href="pcre_table.5.html">pcre</a>:/etc/postfix/reply_filter 9745</pre> 9746 9747<pre> 9748/etc/postfix/reply_filter: 9749 # Transform garbage into "250-filler..." so that it looks like 9750 # one line from a multi-line reply. It does not matter what we 9751 # substitute here as long it has the right syntax. The Postfix 9752 # SMTP client will use the final line's numerical SMTP reply 9753 # code and enhanced status code. 9754 !/^([2-5][0-9][0-9]($|[- ]))/ 250-filler for garbage 9755</pre> 9756 9757<p> This feature is available in Postfix 2.7. </p> 9758 9759 9760</DD> 9761 9762<DT><b><a name="smtp_rset_timeout">smtp_rset_timeout</a> 9763(default: 20s)</b></DT><DD> 9764 9765<p> The SMTP client time limit for sending the RSET command, and 9766for receiving the server response. The SMTP client sends RSET in 9767order to finish a recipient address probe, or to verify that a 9768cached session is still usable. </p> 9769 9770<p> This feature is available in Postfix 2.1 and later. </p> 9771 9772 9773</DD> 9774 9775<DT><b><a name="smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> 9776(default: empty)</b></DT><DD> 9777 9778<p> An optional table to prevent repeated SASL authentication 9779failures with the same remote SMTP server hostname, username and 9780password. Each table (key, value) pair contains a server name, a 9781username and password, and the full server response. This information 9782is stored when a remote SMTP server rejects an authentication attempt 9783with a 535 reply code. As long as the <a href="postconf.5.html#smtp_sasl_password_maps">smtp_sasl_password_maps</a> 9784information does no change, and as long as the <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> 9785information does not expire (see <a href="postconf.5.html#smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a>) the 9786Postfix SMTP client avoids SASL authentication attempts with the 9787same server, username and password, and instead bounces or defers 9788mail as controlled with the <a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> configuration 9789parameter. </p> 9790 9791<p> Use a per-destination delivery concurrency of 1 (for example, 9792"<a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> = 1", 9793"<a href="postconf.5.html#relay_destination_concurrency_limit">relay_destination_concurrency_limit</a> = 1", etc.), otherwise multiple 9794delivery agents may experience a login failure at the same time. 9795</p> 9796 9797<p> The table must be accessed via the proxywrite service, i.e. the 9798map name must start with "<a href="proxymap.8.html">proxy</a>:". The table should be stored under 9799the directory specified with the <a href="postconf.5.html#data_directory">data_directory</a> parameter. </p> 9800 9801<p> This feature uses cryptographic hashing to protect plain-text 9802passwords, and requires that Postfix is compiled with TLS support. 9803</p> 9804 9805<p> Example: </p> 9806 9807<pre> 9808<a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> = <a href="proxymap.8.html">proxy</a>:btree:/var/db/postfix/sasl_auth_cache 9809</pre> 9810 9811<p> This feature is available in Postfix 2.5 and later. </p> 9812 9813 9814</DD> 9815 9816<DT><b><a name="smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a> 9817(default: 90d)</b></DT><DD> 9818 9819<p> The maximal age of an <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> entry before it 9820is removed. </p> 9821 9822<p> This feature is available in Postfix 2.5 and later. </p> 9823 9824 9825</DD> 9826 9827<DT><b><a name="smtp_sasl_auth_enable">smtp_sasl_auth_enable</a> 9828(default: no)</b></DT><DD> 9829 9830<p> 9831Enable SASL authentication in the Postfix SMTP client. By default, 9832the Postfix SMTP client uses no authentication. 9833</p> 9834 9835<p> 9836Example: 9837</p> 9838 9839<pre> 9840<a href="postconf.5.html#smtp_sasl_auth_enable">smtp_sasl_auth_enable</a> = yes 9841</pre> 9842 9843 9844</DD> 9845 9846<DT><b><a name="smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> 9847(default: yes)</b></DT><DD> 9848 9849<p> When a remote SMTP server rejects a SASL authentication request 9850with a 535 reply code, defer mail delivery instead of returning 9851mail as undeliverable. The latter behavior was hard-coded prior to 9852Postfix version 2.5. </p> 9853 9854<p> Note: the setting "yes" overrides the global <a href="postconf.5.html#soft_bounce">soft_bounce</a> 9855parameter, but the setting "no" does not. </p> 9856 9857<p> Example: </p> 9858 9859<pre> 9860# Default as of Postfix 2.5 9861<a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> = yes 9862# The old hard-coded default 9863<a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> = no 9864</pre> 9865 9866<p> This feature is available in Postfix 2.5 and later. </p> 9867 9868 9869</DD> 9870 9871<DT><b><a name="smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> 9872(default: empty)</b></DT><DD> 9873 9874<p> 9875If non-empty, a Postfix SMTP client filter for the remote SMTP 9876server's list of offered SASL mechanisms. Different client and 9877server implementations may support different mechanism lists. By 9878default, the Postfix SMTP client will use the intersection of the 9879two. <a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> further restricts what server 9880mechanisms the client will take into consideration. </p> 9881 9882<p> Specify mechanism names, "/file/name" patterns or "<a href="DATABASE_README.html">type:table</a>" 9883lookup tables. The right-hand side result from "<a href="DATABASE_README.html">type:table</a>" lookups 9884is ignored. Specify "!pattern" to exclude a mechanism name from the 9885list. The form "!/file/name" is supported only in Postfix version 98862.4 and later. </p> 9887 9888<p> This feature is available in Postfix 2.2 and later. </p> 9889 9890<p> 9891Examples: 9892</p> 9893 9894<pre> 9895<a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> = plain, login 9896<a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> = /etc/postfix/smtp_mechs 9897<a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> = !gssapi, !login, static:rest 9898</pre> 9899 9900 9901</DD> 9902 9903<DT><b><a name="smtp_sasl_password_maps">smtp_sasl_password_maps</a> 9904(default: empty)</b></DT><DD> 9905 9906<p> 9907Optional SMTP client lookup tables with one username:password entry 9908per remote hostname or domain, or sender address when sender-dependent 9909authentication is enabled. If no username:password entry is found, 9910then the Postfix SMTP client will not 9911attempt to authenticate to the remote host. 9912</p> 9913 9914<p> 9915The Postfix SMTP client opens the lookup table before going to 9916chroot jail, so you can leave the password file in /etc/postfix. 9917</p> 9918 9919 9920</DD> 9921 9922<DT><b><a name="smtp_sasl_path">smtp_sasl_path</a> 9923(default: empty)</b></DT><DD> 9924 9925<p> Implementation-specific information that the Postfix SMTP client 9926passes through to 9927the SASL plug-in implementation that is selected with 9928<b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>. Typically this specifies the name of a 9929configuration file or rendezvous point. </p> 9930 9931<p> This feature is available in Postfix 2.3 and later. </p> 9932 9933 9934</DD> 9935 9936<DT><b><a name="smtp_sasl_security_options">smtp_sasl_security_options</a> 9937(default: noplaintext, noanonymous)</b></DT><DD> 9938 9939<p> Postfix SMTP client SASL security options; as of Postfix 2.3 9940the list of available 9941features depends on the SASL client implementation that is selected 9942with <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>. </p> 9943 9944<p> The following security features are defined for the <b>cyrus</b> 9945client SASL implementation: </p> 9946 9947<p> 9948Specify zero or more of the following: 9949</p> 9950 9951<dl> 9952 9953<dt><b>noplaintext</b></dt> 9954 9955<dd>Disallow methods that use plaintext passwords. </dd> 9956 9957<dt><b>noactive</b></dt> 9958 9959<dd>Disallow methods subject to active (non-dictionary) attack. 9960</dd> 9961 9962<dt><b>nodictionary</b></dt> 9963 9964<dd>Disallow methods subject to passive (dictionary) attack. </dd> 9965 9966<dt><b>noanonymous</b></dt> 9967 9968<dd>Disallow methods that allow anonymous authentication. </dd> 9969 9970<dt><b>mutual_auth</b></dt> 9971 9972<dd>Only allow methods that provide mutual authentication (not 9973available with SASL version 1). </dd> 9974 9975</dl> 9976 9977<p> 9978Example: 9979</p> 9980 9981<pre> 9982<a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a> = noplaintext 9983</pre> 9984 9985 9986</DD> 9987 9988<DT><b><a name="smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a> 9989(default: $<a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a>)</b></DT><DD> 9990 9991<p> The SASL authentication security options that the Postfix SMTP 9992client uses for TLS encrypted SMTP sessions. </p> 9993 9994<p> This feature is available in Postfix 2.2 and later. </p> 9995 9996 9997</DD> 9998 9999<DT><b><a name="smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a> 10000(default: $<a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a>)</b></DT><DD> 10001 10002<p> The SASL authentication security options that the Postfix SMTP 10003client uses for TLS encrypted SMTP sessions with a verified server 10004certificate. </p> 10005 10006<p> When mail is sent to the public MX host for the recipient's 10007domain, server certificates are by default optional, and delivery 10008proceeds even if certificate verification fails. For delivery via 10009a submission service that requires SASL authentication, it may be 10010appropriate to send plaintext passwords only when the connection 10011to the server is strongly encrypted <b>and</b> the server identity 10012is verified. </p> 10013 10014<p> The <a href="postconf.5.html#smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a> parameter makes it 10015possible to only enable plaintext mechanisms when a secure connection 10016to the server is available. Submission servers subject to this 10017policy must either have verifiable certificates or offer suitable 10018non-plaintext SASL mechanisms. </p> 10019 10020<p> This feature is available in Postfix 2.6 and later. </p> 10021 10022 10023</DD> 10024 10025<DT><b><a name="smtp_sasl_type">smtp_sasl_type</a> 10026(default: cyrus)</b></DT><DD> 10027 10028<p> The SASL plug-in type that the Postfix SMTP client should use 10029for authentication. The available types are listed with the 10030"<b>postconf -A</b>" command. </p> 10031 10032<p> This feature is available in Postfix 2.3 and later. </p> 10033 10034 10035</DD> 10036 10037<DT><b><a name="smtp_send_xforward_command">smtp_send_xforward_command</a> 10038(default: no)</b></DT><DD> 10039 10040<p> 10041Send the non-standard XFORWARD command when the Postfix SMTP server 10042EHLO response announces XFORWARD support. 10043</p> 10044 10045<p> 10046This allows an "smtp" delivery agent, used for injecting mail into 10047a content filter, to forward the name, address, protocol and HELO 10048name of the original client to the content filter and downstream 10049queuing SMTP server. This can produce more useful logging than 10050localhost[127.0.0.1] etc. 10051</p> 10052 10053<p> 10054This feature is available in Postfix 2.1 and later. 10055</p> 10056 10057 10058</DD> 10059 10060<DT><b><a name="smtp_sender_dependent_authentication">smtp_sender_dependent_authentication</a> 10061(default: no)</b></DT><DD> 10062 10063<p> 10064Enable sender-dependent authentication in the Postfix SMTP client; this is 10065available only with SASL authentication, and disables SMTP connection 10066caching to ensure that mail from different senders will use the 10067appropriate credentials. </p> 10068 10069<p> 10070This feature is available in Postfix 2.3 and later. 10071</p> 10072 10073 10074</DD> 10075 10076<DT><b><a name="smtp_skip_4xx_greeting">smtp_skip_4xx_greeting</a> 10077(default: yes)</b></DT><DD> 10078 10079<p> 10080Skip SMTP servers that greet with a 4XX status code (go away, try 10081again later). 10082</p> 10083 10084<p> 10085By default, Postfix moves on the next mail exchanger. Specify 10086"<a href="postconf.5.html#smtp_skip_4xx_greeting">smtp_skip_4xx_greeting</a> = no" if Postfix should defer delivery 10087immediately. 10088</p> 10089 10090<p> This feature is available in Postfix 2.0 and earlier. 10091Later Postfix versions always skip SMTP servers that greet with a 100924XX status code. </p> 10093 10094 10095</DD> 10096 10097<DT><b><a name="smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> 10098(default: yes)</b></DT><DD> 10099 10100<p> 10101Skip SMTP servers that greet with a 5XX status code (go away, do 10102not try again later). 10103</p> 10104 10105<p> By default, the Postfix SMTP client moves on the next mail 10106exchanger. Specify "<a href="postconf.5.html#smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> = no" if Postfix should 10107bounce the mail immediately. The default setting is incorrect, but 10108it is what a lot of people expect to happen. </p> 10109 10110 10111</DD> 10112 10113<DT><b><a name="smtp_skip_quit_response">smtp_skip_quit_response</a> 10114(default: yes)</b></DT><DD> 10115 10116<p> 10117Do not wait for the response to the SMTP QUIT command. 10118</p> 10119 10120 10121</DD> 10122 10123<DT><b><a name="smtp_starttls_timeout">smtp_starttls_timeout</a> 10124(default: 300s)</b></DT><DD> 10125 10126<p> Time limit for Postfix SMTP client write and read operations 10127during TLS startup and shutdown handshake procedures. </p> 10128 10129<p> This feature is available in Postfix 2.2 and later. </p> 10130 10131 10132</DD> 10133 10134<DT><b><a name="smtp_tls_CAfile">smtp_tls_CAfile</a> 10135(default: empty)</b></DT><DD> 10136 10137<p> A file containing CA certificates of root CAs trusted to sign 10138either remote SMTP server certificates or intermediate CA certificates. 10139These are loaded into memory before the <a href="smtp.8.html">smtp(8)</a> client enters the 10140chroot jail. If the number of trusted roots is large, consider using 10141<a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> instead, but note that the latter directory must be 10142present in the chroot jail if the <a href="smtp.8.html">smtp(8)</a> client is chrooted. This 10143file may also be used to augment the client certificate trust chain, 10144but it is best to include all the required certificates directly in 10145$<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>. </p> 10146 10147<p> Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = no" to prevent Postfix from 10148appending the system-supplied default CAs and trusting third-party 10149certificates. </p> 10150 10151<p> Example: </p> 10152 10153<pre> 10154<a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a> = /etc/postfix/CAcert.pem 10155</pre> 10156 10157<p> This feature is available in Postfix 2.2 and later. </p> 10158 10159 10160</DD> 10161 10162<DT><b><a name="smtp_tls_CApath">smtp_tls_CApath</a> 10163(default: empty)</b></DT><DD> 10164 10165<p> Directory with PEM format certificate authority certificates 10166that the Postfix SMTP client uses to verify a remote SMTP server 10167certificate. Don't forget to create the necessary "hash" links 10168with, for example, "$OPENSSL_HOME/bin/c_rehash /etc/postfix/certs". 10169</p> 10170 10171<p> To use this option in chroot mode, this directory (or a copy) 10172must be inside the chroot jail. </p> 10173 10174<p> Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = no" to prevent Postfix from 10175appending the system-supplied default CAs and trusting third-party 10176certificates. </p> 10177 10178<p> Example: </p> 10179 10180<pre> 10181<a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> = /etc/postfix/certs 10182</pre> 10183 10184<p> This feature is available in Postfix 2.2 and later. </p> 10185 10186 10187</DD> 10188 10189<DT><b><a name="smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> 10190(default: no)</b></DT><DD> 10191 10192<p> Try to detect a mail hijacking attack based on a TLS protocol 10193vulnerability (CVE-2009-3555), where an attacker prepends malicious 10194HELO, MAIL, RCPT, DATA commands to a Postfix SMTP client TLS session. 10195The attack would succeed with non-Postfix SMTP servers that reply 10196to the malicious HELO, MAIL, RCPT, DATA commands after negotiating 10197the Postfix SMTP client TLS session. </p> 10198 10199<p> This feature is available in Postfix 2.7. </p> 10200 10201 10202</DD> 10203 10204<DT><b><a name="smtp_tls_cert_file">smtp_tls_cert_file</a> 10205(default: empty)</b></DT><DD> 10206 10207<p> File with the Postfix SMTP client RSA certificate in PEM format. 10208This file may also contain the Postfix SMTP client private RSA key, 10209and these may be the same as the Postfix SMTP server RSA certificate and key 10210file. </p> 10211 10212<p> Do not configure client certificates unless you <b>must</b> present 10213client TLS certificates to one or more servers. Client certificates are 10214not usually needed, and can cause problems in configurations that work 10215well without them. The recommended setting is to let the defaults stand: </p> 10216 10217<blockquote> 10218<pre> 10219<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> = 10220<a href="postconf.5.html#smtp_tls_key_file">smtp_tls_key_file</a> = 10221<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> = 10222<a href="postconf.5.html#smtp_tls_dkey_file">smtp_tls_dkey_file</a> = 10223<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> = 10224<a href="postconf.5.html#smtp_tls_eckey_file">smtp_tls_eckey_file</a> = 10225</pre> 10226</blockquote> 10227 10228<p> The best way to use the default settings is to comment out the above 10229parameters in <a href="postconf.5.html">main.cf</a> if present. </p> 10230 10231<p> To enable remote SMTP servers to verify the Postfix SMTP client 10232certificate, the issuing CA certificates must be made available to the 10233server. You should include the required certificates in the client 10234certificate file, the client certificate first, then the issuing 10235CA(s) (bottom-up order). </p> 10236 10237<p> Example: the certificate for "client.example.com" was issued by 10238"intermediate CA" which itself has a certificate issued by "root CA". 10239Create the client.pem file with "cat client_cert.pem intermediate_CA.pem 10240root_CA.pem > client.pem". </p> 10241 10242<p> If you also want to verify remote SMTP server certificates issued by 10243these CAs, you can add the CA certificates to the <a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a>, in 10244which case it is not necessary to have them in the <a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>, 10245<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> or <a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>. </p> 10246 10247<p> A certificate supplied here must be usable as an SSL client certificate 10248and hence pass the "openssl verify -purpose sslclient ..." test. </p> 10249 10250<p> Example: </p> 10251 10252<pre> 10253<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> = /etc/postfix/client.pem 10254</pre> 10255 10256<p> This feature is available in Postfix 2.2 and later. </p> 10257 10258 10259</DD> 10260 10261<DT><b><a name="smtp_tls_cipherlist">smtp_tls_cipherlist</a> 10262(default: empty)</b></DT><DD> 10263 10264<p> Obsolete Postfix < 2.3 control for the Postfix SMTP client TLS 10265cipher list. As this feature applies to all TLS security levels, it is easy 10266to create inter-operability problems by choosing a non-default cipher 10267list. Do not use a non-default TLS cipher list on hosts that deliver email 10268to the public Internet: you will be unable to send email to servers that 10269only support the ciphers you exclude. Using a restricted cipher list 10270may be more appropriate for an internal MTA, where one can exert some 10271control over the TLS software and settings of the peer servers. </p> 10272 10273<p> <b>Note:</b> do not use "" quotes around the parameter value. </p> 10274 10275<p> This feature is available in Postfix version 2.2. It is not used with 10276Postfix 2.3 and later; use <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> instead. </p> 10277 10278 10279</DD> 10280 10281<DT><b><a name="smtp_tls_ciphers">smtp_tls_ciphers</a> 10282(default: export)</b></DT><DD> 10283 10284<p> The minimum TLS cipher grade that the Postfix SMTP client 10285will use with opportunistic TLS encryption. Cipher types listed in 10286<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> are excluded from the base definition of 10287the selected cipher grade. The default value "export" ensures maximum 10288inter-operability. Because encryption is optional, stronger controls 10289are not appropriate, and this setting SHOULD NOT be changed unless the 10290change is essential. </p> 10291 10292<p> When TLS is mandatory the cipher grade is chosen via the 10293<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> configuration parameter, see there for syntax 10294details. See <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> for information on how to configure 10295ciphers on a per-destination basis. </p> 10296 10297<p> Example: </p> 10298<pre> 10299<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = export 10300</pre> 10301 10302<p> This feature is available in Postfix 2.6 and later. With earlier Postfix 10303releases only the <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> parameter is implemented, 10304and opportunistic TLS always uses "export" or better (i.e. all) ciphers. </p> 10305 10306 10307</DD> 10308 10309<DT><b><a name="smtp_tls_dcert_file">smtp_tls_dcert_file</a> 10310(default: empty)</b></DT><DD> 10311 10312<p> File with the Postfix SMTP client DSA certificate in PEM format. 10313This file may also contain the Postfix SMTP client private DSA key. </p> 10314 10315<p> See the discussion under <a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> for more details. 10316</p> 10317 10318<p> Example: </p> 10319 10320<pre> 10321<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> = /etc/postfix/client-dsa.pem 10322</pre> 10323 10324<p> This feature is available in Postfix 2.2 and later. </p> 10325 10326 10327</DD> 10328 10329<DT><b><a name="smtp_tls_dkey_file">smtp_tls_dkey_file</a> 10330(default: $<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a>)</b></DT><DD> 10331 10332<p> File with the Postfix SMTP client DSA private key in PEM format. 10333This file may be combined with the Postfix SMTP client DSA certificate 10334file specified with $<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a>. </p> 10335 10336<p> The private key must be accessible without a pass-phrase, i.e. it 10337must not be encrypted. File permissions should grant read-only 10338access to the system superuser account ("root"), and no access 10339to anyone else. </p> 10340 10341<p> This feature is available in Postfix 2.2 and later. </p> 10342 10343 10344</DD> 10345 10346<DT><b><a name="smtp_tls_eccert_file">smtp_tls_eccert_file</a> 10347(default: empty)</b></DT><DD> 10348 10349<p> File with the Postfix SMTP client ECDSA certificate in PEM format. 10350This file may also contain the Postfix SMTP client ECDSA private key. </p> 10351 10352<p> See the discussion under <a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> for more details. 10353</p> 10354 10355<p> Example: </p> 10356 10357<pre> 10358<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> = /etc/postfix/ecdsa-ccert.pem 10359</pre> 10360 10361<p> This feature is available in Postfix 2.6 and later, when Postfix is 10362compiled and linked with OpenSSL 1.0.0 or later. </p> 10363 10364 10365</DD> 10366 10367<DT><b><a name="smtp_tls_eckey_file">smtp_tls_eckey_file</a> 10368(default: $<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>)</b></DT><DD> 10369 10370<p> File with the Postfix SMTP client ECDSA private key in PEM format. 10371This file may be combined with the Postfix SMTP client ECDSA 10372certificate file specified with $<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>. </p> 10373 10374<p> The private key must be accessible without a pass-phrase, i.e. it 10375must not be encrypted. File permissions should grant read-only 10376access to the system superuser account ("root"), and no access 10377to anyone else. </p> 10378 10379<p> This feature is available in Postfix 2.6 and later, when Postfix is 10380compiled and linked with OpenSSL 1.0.0 or later. </p> 10381 10382 10383</DD> 10384 10385<DT><b><a name="smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> 10386(default: yes)</b></DT><DD> 10387 10388<p> With mandatory TLS encryption, require that the remote SMTP 10389server hostname matches the information in the remote SMTP server 10390certificate. As of <a href="http://tools.ietf.org/html/rfc2487">RFC 2487</a> the requirements for hostname checking 10391for MTA clients are not specified. </p> 10392 10393<p> This option can be set to "no" to disable strict peer name 10394checking. This setting has no effect on sessions that are controlled 10395via the <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> table. </p> 10396 10397<p> Disabling the hostname verification can make sense in closed 10398environment where special CAs are created. If not used carefully, 10399this option opens the danger of a "man-in-the-middle" attack (the 10400CommonName of this attacker will be logged). </p> 10401 10402<p> This feature is available in Postfix 2.2 and later. With 10403Postfix 2.3 and later use <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> instead. </p> 10404 10405 10406</DD> 10407 10408<DT><b><a name="smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> 10409(default: empty)</b></DT><DD> 10410 10411<p> List of ciphers or cipher types to exclude from the Postfix 10412SMTP client cipher 10413list at all TLS security levels. This is not an OpenSSL cipherlist, it is 10414a simple list separated by whitespace and/or commas. The elements are a 10415single cipher, or one or more "+" separated cipher properties, in which 10416case only ciphers matching <b>all</b> the properties are excluded. </p> 10417 10418<p> Examples (some of these will cause problems): </p> 10419 10420<blockquote> 10421<pre> 10422<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = aNULL 10423<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = MD5, DES 10424<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = DES+MD5 10425<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = AES256-SHA, DES-CBC3-MD5 10426<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = kEDH+aRSA 10427</pre> 10428</blockquote> 10429 10430<p> The first setting, disables anonymous ciphers. The next setting 10431disables ciphers that use the MD5 digest algorithm or the (single) DES 10432encryption algorithm. The next setting disables ciphers that use MD5 and 10433DES together. The next setting disables the two ciphers "AES256-SHA" 10434and "DES-CBC3-MD5". The last setting disables ciphers that use "EDH" 10435key exchange with RSA authentication. </p> 10436 10437<p> This feature is available in Postfix 2.3 and later. </p> 10438 10439 10440</DD> 10441 10442<DT><b><a name="smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> 10443(default: empty)</b></DT><DD> 10444 10445<p> List of acceptable remote SMTP server certificate fingerprints 10446for the "fingerprint" TLS security level (<b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a></b> = 10447fingerprint). At this security level, certificate authorities are 10448not used, and certificate expiration times are ignored. Instead, 10449server certificates are verified directly via their "fingerprint". The 10450fingerprint is a message digest of the server certificate. The digest 10451algorithm is selected via the <b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a></b> 10452parameter. </p> 10453 10454<p> When an <b><a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a></b> table entry specifies the 10455"fingerprint" security level, any "match" attributes in that entry specify 10456the list of valid fingerprints for the corresponding destination. Multiple 10457fingerprints can be combined with a "|" delimiter in a single match 10458attribute, or multiple match attributes can be employed. </p> 10459 10460<p> Example: Certificate fingerprint verification with internal mailhub. 10461Two matching fingerprints are listed. The <a href="postconf.5.html#relayhost">relayhost</a> may be multiple 10462physical hosts behind a load-balancer, each with its own private/public 10463key and self-signed certificate. Alternatively, a single <a href="postconf.5.html#relayhost">relayhost</a> may 10464be in the process of switching from one set of private/public keys to 10465another, and both keys are trusted just prior to the transition. </p> 10466 10467<blockquote> 10468<pre> 10469<a href="postconf.5.html#relayhost">relayhost</a> = [mailhub.example.com] 10470<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = fingerprint 10471<a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> = md5 10472<a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> = 10473 3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 10474 EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 10475</pre> 10476</blockquote> 10477 10478<p> Example: Certificate fingerprint verification with selected destinations. 10479As in the example above, we show two matching fingerprints: </p> 10480 10481<blockquote> 10482<pre> 10483/etc/postfix/<a href="postconf.5.html">main.cf</a>: 10484 <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> = hash:/etc/postfix/tls_policy 10485 <a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> = md5 10486</pre> 10487</blockquote> 10488 10489<blockquote> 10490<pre> 10491/etc/postfix/tls_policy: 10492 example.com fingerprint 10493 match=3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 10494 match=EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 10495</pre> 10496</blockquote> 10497 10498<p> This feature is available in Postfix 2.5 and later. </p> 10499 10500 10501</DD> 10502 10503<DT><b><a name="smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> 10504(default: md5)</b></DT><DD> 10505 10506<p> The message digest algorithm used to construct remote SMTP server 10507certificate fingerprints. At the "fingerprint" TLS security level 10508(<b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a></b> = fingerprint), the server certificate is 10509verified by directly matching its <i>fingerprint</i>. The fingerprint 10510is the message digest of the server certificate using the selected 10511algorithm. With a digest algorithm resistant to "second pre-image" 10512attacks, it is not feasible to create a new public key and a matching 10513certificate that has the same fingerprint. </p> 10514 10515<p> The default algorithm is <b>md5</b>; this is consistent with 10516the backwards compatible setting of the digest used to verify client 10517certificates in the SMTP server. </p> 10518 10519<p> The best practice algorithm is now <b>sha1</b>. Recent advances in hash 10520function cryptanalysis have led to md5 being deprecated in favor of sha1. 10521However, as long as there are no known "second pre-image" attacks 10522against md5, its use in this context can still be considered safe. 10523</p> 10524 10525<p> While additional digest algorithms are often available with OpenSSL's 10526libcrypto, only those used by libssl in SSL cipher suites are available to 10527Postfix. For now this means just md5 or sha1. </p> 10528 10529<p> To find the fingerprint of a specific certificate file, with a 10530specific digest algorithm, run: 10531</p> 10532 10533<blockquote> 10534<pre> 10535$ openssl x509 -noout -fingerprint -<i>digest</i> -in <i>certfile</i>.pem 10536</pre> 10537</blockquote> 10538 10539<p> The text to the right of "=" sign is the desired fingerprint. 10540For example: </p> 10541 10542<blockquote> 10543<pre> 10544$ openssl x509 -noout -fingerprint -sha1 -in cert.pem 10545SHA1 Fingerprint=D4:6A:AB:19:24:79:F8:32:BB:A6:CB:66:82:C0:8E:9B:EE:29:A8:1A 10546</pre> 10547</blockquote> 10548 10549<p> This feature is available in Postfix 2.5 and later. </p> 10550 10551 10552</DD> 10553 10554<DT><b><a name="smtp_tls_key_file">smtp_tls_key_file</a> 10555(default: $<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>)</b></DT><DD> 10556 10557<p> File with the Postfix SMTP client RSA private key in PEM format. 10558This file may be combined with the Postfix SMTP client RSA certificate 10559file specified with $<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>. </p> 10560 10561<p> The private key must be accessible without a pass-phrase, i.e. it 10562must not be encrypted. File permissions should grant read-only 10563access to the system superuser account ("root"), and no access 10564to anyone else. </p> 10565 10566<p> Example: </p> 10567 10568<pre> 10569<a href="postconf.5.html#smtp_tls_key_file">smtp_tls_key_file</a> = $<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> 10570</pre> 10571 10572<p> This feature is available in Postfix 2.2 and later. </p> 10573 10574 10575</DD> 10576 10577<DT><b><a name="smtp_tls_loglevel">smtp_tls_loglevel</a> 10578(default: 0)</b></DT><DD> 10579 10580<p> Enable additional Postfix SMTP client logging of TLS activity. 10581Each logging level also includes the information that is logged at 10582a lower logging level. </p> 10583 10584<dl compact> 10585 10586<dt> </dt> <dd> 0 Disable logging of TLS activity. </dd> 10587 10588<dt> </dt> <dd> 1 Log TLS handshake and certificate information. </dd> 10589 10590<dt> </dt> <dd> 2 Log levels during TLS negotiation. </dd> 10591 10592<dt> </dt> <dd> 3 Log hexadecimal and ASCII dump of TLS negotiation 10593process. </dd> 10594 10595<dt> </dt> <dd> 4 Log hexadecimal and ASCII dump of complete 10596transmission after STARTTLS. </dd> 10597 10598</dl> 10599 10600<p> Use "<a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> = 3" only in case of problems. Use of 10601loglevel 4 is strongly discouraged. </p> 10602 10603<p> This feature is available in Postfix 2.2 and later. </p> 10604 10605 10606</DD> 10607 10608<DT><b><a name="smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> 10609(default: medium)</b></DT><DD> 10610 10611<p> The minimum TLS cipher grade that the Postfix SMTP client will 10612use with 10613mandatory TLS encryption. The default value "medium" is suitable 10614for most destinations with which you may want to enforce TLS, and 10615is beyond the reach of today's cryptanalytic methods. See 10616<a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> for information on how to configure ciphers 10617on a per-destination basis. </p> 10618 10619<p> The following cipher grades are supported: </p> 10620 10621<dl> 10622<dt><b>export</b></dt> 10623<dd> Enable "EXPORT" grade or better OpenSSL 10624ciphers. This is the default for opportunistic encryption. It is 10625not recommended for mandatory encryption unless you must enforce TLS 10626with "crippled" peers. The underlying cipherlist is specified via the 10627<a href="postconf.5.html#tls_export_cipherlist">tls_export_cipherlist</a> configuration parameter, which you are strongly 10628encouraged to not change. </dd> 10629 10630<dt><b>low</b></dt> 10631<dd> Enable "LOW" grade or better OpenSSL ciphers. This 10632setting is only appropriate for internal mail servers. The underlying 10633cipherlist is specified via the <a href="postconf.5.html#tls_low_cipherlist">tls_low_cipherlist</a> configuration 10634parameter, which you are strongly encouraged to not change. </dd> 10635 10636<dt><b>medium</b></dt> 10637<dd> Enable "MEDIUM" grade or better OpenSSL ciphers. 10638The underlying cipherlist is specified via the <a href="postconf.5.html#tls_medium_cipherlist">tls_medium_cipherlist</a> 10639configuration parameter, which you are strongly encouraged to not change. 10640</dd> 10641 10642<dt><b>high</b></dt> 10643<dd> Enable only "HIGH" grade OpenSSL ciphers. This setting may 10644be appropriate when all mandatory TLS destinations (e.g. when all 10645mail is routed to a suitably capable <a href="postconf.5.html#relayhost">relayhost</a>) support at least one 10646"HIGH" grade cipher. The underlying cipherlist is specified via the 10647<a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a> configuration parameter, which you are strongly 10648encouraged to not change. </dd> 10649 10650<dt><b>null</b></dt> 10651<dd> Enable only the "NULL" OpenSSL ciphers, these provide authentication 10652without encryption. This setting is only appropriate in the rare case 10653that all servers are prepared to use NULL ciphers (not normally enabled 10654in TLS servers). A plausible use-case is an LMTP server listening on a 10655UNIX-domain socket that is configured to support "NULL" ciphers. The 10656underlying cipherlist is specified via the <a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> 10657configuration parameter, which you are strongly encouraged to not 10658change. </dd> 10659 10660</dl> 10661 10662<p> The underlying cipherlists for grades other than "null" include 10663anonymous ciphers, but these are automatically filtered out if the 10664Postfix SMTP client is configured to verify server certificates. 10665You are very unlikely to need to take any steps to exclude anonymous 10666ciphers, they are excluded automatically as necessary. If you must 10667exclude anonymous ciphers at the "may" or "encrypt" security levels, 10668when the Postfix SMTP client does not need or use peer certificates, set 10669"<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = aNULL". To exclude anonymous ciphers only when 10670TLS is enforced, set "<a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> = aNULL". </p> 10671 10672<p> This feature is available in Postfix 2.3 and later. </p> 10673 10674 10675</DD> 10676 10677<DT><b><a name="smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> 10678(default: empty)</b></DT><DD> 10679 10680<p> Additional list of ciphers or cipher types to exclude from the 10681SMTP client cipher list at mandatory TLS security levels. This list 10682works in addition to the exclusions listed with <a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> 10683(see there for syntax details). </p> 10684 10685<p> Starting with Postfix 2.6, the mandatory cipher exclusions can be 10686specified on a per-destination basis via the TLS policy "exclude" 10687attribute. See <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> for notes and examples. </p> 10688 10689<p> This feature is available in Postfix 2.3 and later. </p> 10690 10691 10692</DD> 10693 10694<DT><b><a name="smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> 10695(default: SSLv3, TLSv1)</b></DT><DD> 10696 10697<p> List of SSL/TLS protocols that the Postfix SMTP client will use with 10698mandatory TLS encryption. In <a href="postconf.5.html">main.cf</a> the values are separated by 10699whitespace, commas or colons. In the policy table "protocols" attribute 10700(see <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid separator is colon. An 10701empty value means allow all protocols. The valid protocol names, (see 10702<b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" and "TLSv1". </p> 10703 10704<p> With Postfix ≥ 2.5 the parameter syntax is expanded to support 10705protocol exclusions. One can now explicitly exclude SSLv2 by setting 10706"<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2". To exclude both SSLv2 and 10707SSLv3 set "<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3". Listing 10708the protocols to include, rather than protocols to exclude, is still 10709supported; use the form you find more intuitive. </p> 10710 10711<p> Since SSL version 2 has known protocol weaknesses and is now 10712deprecated, the default setting excludes "SSLv2". This means that by 10713default, SSL version 2 will not be used at the "encrypt" security level 10714and higher. </p> 10715 10716<p> See the documentation of the <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> parameter and 10717<a href="TLS_README.html">TLS_README</a> for more information about security levels. </p> 10718 10719<p> Example: </p> 10720 10721<pre> 10722<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = TLSv1 10723# Alternative form with Postfix ≥ 2.5: 10724<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 10725</pre> 10726 10727<p> This feature is available in Postfix 2.3 and later. </p> 10728 10729 10730</DD> 10731 10732<DT><b><a name="smtp_tls_note_starttls_offer">smtp_tls_note_starttls_offer</a> 10733(default: no)</b></DT><DD> 10734 10735<p> Log the hostname of a remote SMTP server that offers STARTTLS, 10736when TLS is not already enabled for that server. </p> 10737 10738<p> The logfile record looks like: </p> 10739 10740<pre> 10741postfix/smtp[pid]: Host offered STARTTLS: [name.of.host] 10742</pre> 10743 10744<p> This feature is available in Postfix 2.2 and later. </p> 10745 10746 10747</DD> 10748 10749<DT><b><a name="smtp_tls_per_site">smtp_tls_per_site</a> 10750(default: empty)</b></DT><DD> 10751 10752<p> Optional lookup tables with the Postfix SMTP client TLS usage 10753policy by next-hop destination and by remote SMTP server hostname. 10754When both lookups succeed, the more specific per-site policy (NONE, 10755MUST, etc) overrides the less specific one (MAY), and the more secure 10756per-site policy (MUST, etc) overrides the less secure one (NONE). 10757With Postfix 2.3 and later <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> is strongly discouraged: 10758use <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> instead. </p> 10759 10760<p> Use of the bare hostname as the per-site table lookup key is 10761discouraged. Always use the full destination nexthop (enclosed in 10762[] with a possible ":port" suffix). A recipient domain or MX-enabled 10763transport next-hop with no port suffix may look like a bare hostname, 10764but is still a suitable <i>destination</i>. </p> 10765 10766<p> Specify a next-hop destination or server hostname on the left-hand 10767side; no wildcards are allowed. The next-hop destination is either 10768the recipient domain, or the destination specified with a <a href="transport.5.html">transport(5)</a> 10769table, the <a href="postconf.5.html#relayhost">relayhost</a> parameter, or the <a href="postconf.5.html#relay_transport">relay_transport</a> parameter. 10770On the right hand side specify one of the following keywords: </p> 10771 10772<dl> 10773 10774<dt> NONE </dt> <dd> Don't use TLS at all. This overrides a less 10775specific <b>MAY</b> lookup result from the alternate host or next-hop 10776lookup key, and overrides the global <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>, <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a>, 10777and <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> settings. </dd> 10778 10779<dt> MAY </dt> <dd> Try to use TLS if the server announces support, 10780otherwise use the unencrypted connection. This has less precedence 10781than a more specific result (including <b>NONE</b>) from the alternate 10782host or next-hop lookup key, and has less precedence than the more 10783specific global "<a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> = yes" or "<a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> 10784= yes". </dd> 10785 10786<dt> MUST_NOPEERMATCH </dt> <dd> Require TLS encryption, but do not 10787require that the remote SMTP server hostname matches the information 10788in the remote SMTP server certificate, or that the server certificate 10789was issued by a trusted CA. This overrides a less secure <b>NONE</b> 10790or a less specific <b>MAY</b> lookup result from the alternate host 10791or next-hop lookup key, and overrides the global <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>, 10792<a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> and <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> settings. </dd> 10793 10794<dt> MUST </dt> <dd> Require TLS encryption, require that the remote 10795SMTP server hostname matches the information in the remote SMTP 10796server certificate, and require that the remote SMTP server certificate 10797was issued by a trusted CA. This overrides a less secure <b>NONE</b> 10798and <b>MUST_NOPEERMATCH</b> or a less specific <b>MAY</b> lookup 10799result from the alternate host or next-hop lookup key, and overrides 10800the global <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>, <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> and <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> 10801settings. </dd> 10802 10803</dl> 10804 10805<p> The above keywords correspond to the "none", "may", "encrypt" and 10806"verify" security levels for the new <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> parameter 10807introduced in Postfix 2.3. Starting with Postfix 2.3, and independently 10808of how the policy is specified, the <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and 10809<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> parameters apply when TLS encryption 10810is mandatory. Connections for which encryption is optional typically 10811enable all "export" grade and better ciphers (see <a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> 10812and <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a>). </p> 10813 10814<p> As long as no secure DNS lookup mechanism is available, false 10815hostnames in MX or CNAME responses can change the server hostname 10816that Postfix uses for TLS policy lookup and server certificate 10817verification. Even with a perfect match between the server hostname and 10818the server certificate, there is no guarantee that Postfix is connected 10819to the right server. See <a href="TLS_README.html">TLS_README</a> (Closing a DNS loophole with obsolete 10820per-site TLS policies) for a possible work-around. </p> 10821 10822<p> This feature is available in Postfix 2.2 and later. With 10823Postfix 2.3 and later use <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> instead. </p> 10824 10825 10826</DD> 10827 10828<DT><b><a name="smtp_tls_policy_maps">smtp_tls_policy_maps</a> 10829(default: empty)</b></DT><DD> 10830 10831<p> Optional lookup tables with the Postfix SMTP client TLS security 10832policy by next-hop destination; when a non-empty value is specified, 10833this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter. See 10834<a href="TLS_README.html">TLS_README</a> for a more detailed discussion of TLS security levels. 10835</p> 10836 10837<p> The TLS policy table is indexed by the full next-hop destination, 10838which is either the recipient domain, or the verbatim next-hop 10839specified in the transport table, $<a href="postconf.5.html#local_transport">local_transport</a>, $<a href="postconf.5.html#virtual_transport">virtual_transport</a>, 10840$<a href="postconf.5.html#relay_transport">relay_transport</a> or $<a href="postconf.5.html#default_transport">default_transport</a>. This includes any enclosing 10841square brackets and any non-default destination server port suffix. The 10842LMTP socket type prefix (inet: or unix:) is not included in the lookup 10843key. </p> 10844 10845<p> Only the next-hop domain, or $<a href="postconf.5.html#myhostname">myhostname</a> with LMTP over UNIX-domain 10846sockets, is used as the nexthop name for certificate verification. The 10847port and any enclosing square brackets are used in the table lookup key, 10848but are not used for server name verification. </p> 10849 10850<p> When the lookup key is a domain name without enclosing square brackets 10851or any <i>:port</i> suffix (typically the recipient domain), and the full 10852domain is not found in the table, just as with the <a href="transport.5.html">transport(5)</a> table, 10853the parent domain starting with a leading "." is matched recursively. This 10854allows one to specify a security policy for a recipient domain and all 10855its sub-domains. </p> 10856 10857<p> The lookup result is a security level, followed by an optional list 10858of whitespace and/or comma separated name=value attributes that override 10859related <a href="postconf.5.html">main.cf</a> settings. The TLS security levels in order of increasing 10860security are: </p> 10861 10862<dl> 10863 10864<dt><b>none</b></dt> 10865<dd>No TLS. No additional attributes are supported at this level. </dd> 10866 10867<dt><b>may</b></dt> 10868<dd>Opportunistic TLS. Since sending in the clear is acceptable, 10869demanding stronger than default TLS security merely reduces 10870inter-operability. The optional "ciphers", "exclude" and "protocols" 10871attributes (available for opportunistic TLS with Postfix ≥ 2.6) 10872override the "<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a>", "<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a>" and 10873"<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a>" configuration parameters. When opportunistic TLS 10874handshakes fail, Postfix retries the connection with TLS disabled. 10875This allows mail delivery to sites with non-interoperable TLS 10876implementations.</dd> 10877 10878<dt><b>encrypt</b></dt> <dd>Mandatory TLS encryption. At this level 10879and higher, the optional "protocols" attribute overrides the <a href="postconf.5.html">main.cf</a> 10880<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> parameter, the optional "ciphers" attribute 10881overrides the <a href="postconf.5.html">main.cf</a> <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> parameter, and the 10882optional "exclude" attribute (Postfix ≥ 2.6) overrides the <a href="postconf.5.html">main.cf</a> 10883<a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> parameter. In the policy table, 10884multiple protocols or excluded ciphers must be separated by colons, 10885as attribute values may not contain whitespace or commas. </dd> 10886 10887<dt><b>fingerprint</b></dt> <dd>Certificate fingerprint 10888verification. Available with Postfix 2.5 and later. At this security 10889level, there are no trusted certificate authorities. The certificate 10890trust chain, expiration date, ... are not checked. Instead, 10891the optional <b>match</b> attribute, or else the <a href="postconf.5.html">main.cf</a> 10892<b><a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a></b> parameter, lists the 10893valid "fingerprints" of the server certificate. The digest 10894algorithm used to calculate the fingerprint is selected by the 10895<b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a></b> parameter. Multiple fingerprints can 10896be combined with a "|" delimiter in a single match attribute, or multiple 10897match attributes can be employed. The ":" character is not used as a 10898delimiter as it occurs between each pair of fingerprint (hexadecimal) 10899digits. </dd> 10900 10901<dt><b>verify</b></dt> <dd>Mandatory TLS verification. At this security 10902level, DNS MX lookups are trusted to be secure enough, and the name 10903verified in the server certificate is usually obtained indirectly via 10904unauthenticated DNS MX lookups. The optional "match" attribute overrides 10905the <a href="postconf.5.html">main.cf</a> <a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> parameter. In the policy table, 10906multiple match patterns and strategies must be separated by colons. 10907In practice explicit control over matching is more common with the 10908"secure" policy, described below. </dd> 10909 10910<dt><b>secure</b></dt> <dd>Secure-channel TLS. At this security level, DNS 10911MX lookups, though potentially used to determine the candidate next-hop 10912gateway IP addresses, are <b>not</b> trusted to be secure enough for TLS 10913peername verification. Instead, the default name verified in the server 10914certificate is obtained directly from the next-hop, or is explicitly 10915specified via the optional <b>match</b> attribute which overrides the 10916<a href="postconf.5.html">main.cf</a> <a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> parameter. In the policy table, 10917multiple match patterns and strategies must be separated by colons. 10918The match attribute is most useful when multiple domains are supported by 10919common server, the policy entries for additional domains specify matching 10920rules for the primary domain certificate. While transport table overrides 10921routing the secondary domains to the primary nexthop also allow secure 10922verification, they risk delivery to the wrong destination when domains 10923change hands or are re-assigned to new gateways. With the "match" 10924attribute approach, routing is not perturbed, and mail is deferred if 10925verification of a new MX host fails. </dd> 10926 10927</dl> 10928 10929<p> 10930Example: 10931</p> 10932 10933<pre> 10934/etc/postfix/<a href="postconf.5.html">main.cf</a>: 10935 <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> = hash:/etc/postfix/tls_policy 10936 # Postfix 2.5 and later 10937 <a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> = md5 10938</pre> 10939 10940<pre> 10941/etc/postfix/tls_policy: 10942 example.edu none 10943 example.mil may 10944 example.gov encrypt protocols=TLSv1 10945 example.com verify ciphers=high 10946 example.net secure 10947 .example.net secure match=.example.net:example.net 10948 [mail.example.org]:587 secure match=nexthop 10949 # Postfix 2.5 and later 10950 [thumb.example.org] fingerprint 10951 match=EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 10952 match=3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 10953</pre> 10954 10955<p> <b>Note:</b> The <b>hostname</b> strategy if listed in a non-default 10956setting of <a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> or in the <b>match</b> attribute 10957in the policy table can render the <b>secure</b> level vulnerable to 10958DNS forgery. Do not use the <b>hostname</b> strategy for secure-channel 10959configurations in environments where DNS security is not assured. </p> 10960 10961<p> This feature is available in Postfix 2.3 and later. </p> 10962 10963 10964</DD> 10965 10966<DT><b><a name="smtp_tls_protocols">smtp_tls_protocols</a> 10967(default: !SSLv2)</b></DT><DD> 10968 10969<p> List of TLS protocols that the Postfix SMTP client will exclude or 10970include with opportunistic TLS encryption. Starting with Postfix 2.6, 10971the Postfix SMTP client will by default not use the obsolete SSLv2 10972protocol. </p> 10973 10974<p> In <a href="postconf.5.html">main.cf</a> the values are separated by whitespace, commas or 10975colons. In the policy table (see <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid 10976separator is colon. An empty value means allow all protocols. The valid 10977protocol names, (see <b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" 10978and "TLSv1". </p> 10979 10980<p> To include a protocol list its name, to exclude it, prefix the name 10981with a "!" character. To exclude SSLv2 even for opportunistic TLS set 10982"<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2". To exclude both "SSLv2" and "SSLv3" set 10983"<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3". Explicitly listing the protocols to 10984include, is supported, but not recommended. OpenSSL provides no mechanisms 10985for excluding protocols not known at compile-time. If Postfix is linked 10986against an OpenSSL library that supports additional protocol versions, 10987they cannot be excluded using either syntax. </p> 10988 10989<p> Example: </p> 10990<pre> 10991# TLSv1 only! 10992<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3 10993</pre> 10994 10995<p> This feature is available in Postfix 2.6 and later. </p> 10996 10997 10998</DD> 10999 11000<DT><b><a name="smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> 11001(default: 9)</b></DT><DD> 11002 11003<p> The verification depth for remote SMTP server certificates. A depth 11004of 1 is sufficient if the issuing CA is listed in a local CA file. </p> 11005 11006<p> The default verification depth is 9 (the OpenSSL default) for 11007compatibility with earlier Postfix behavior. Prior to Postfix 2.5, 11008the default value was 5, but the limit was not actually enforced. If 11009you have set this to a lower non-default value, certificates with longer 11010trust chains may now fail to verify. Certificate chains with 1 or 2 11011CAs are common, deeper chains are more rare and any number between 5 11012and 9 should suffice in practice. You can choose a lower number if, 11013for example, you trust certificates directly signed by an issuing CA 11014but not any CAs it delegates to. </p> 11015 11016<p> This feature is available in Postfix 2.2 and later. </p> 11017 11018 11019</DD> 11020 11021<DT><b><a name="smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> 11022(default: nexthop, dot-nexthop)</b></DT><DD> 11023 11024<p> The server certificate peername verification method for the 11025"secure" TLS security level. In a "secure" TLS policy table 11026($<a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) entry the optional "match" attribute 11027overrides this <a href="postconf.5.html">main.cf</a> setting. </p> 11028 11029<p> This parameter specifies one or more patterns or strategies separated 11030by commas, whitespace or colons. In the policy table the only valid 11031separator is the colon character. </p> 11032 11033<p> For a description of the pattern and strategy syntax see the 11034<a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> parameter. The "hostname" strategy should 11035be avoided in this context, as in the absence of a secure global DNS, using 11036the results of MX lookups in certificate verification is not immune to active 11037(man-in-the-middle) attacks on DNS. </p> 11038 11039<p> 11040Sample <a href="postconf.5.html">main.cf</a> setting: 11041</p> 11042 11043<blockquote> 11044<pre> 11045<a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> = nexthop 11046</pre> 11047</blockquote> 11048 11049<p> 11050Sample policy table override: 11051</p> 11052 11053<blockquote> 11054<pre> 11055example.net secure match=example.com:.example.com 11056.example.net secure match=example.com:.example.com 11057</pre> 11058</blockquote> 11059 11060<p> This feature is available in Postfix 2.3 and later. </p> 11061 11062 11063</DD> 11064 11065<DT><b><a name="smtp_tls_security_level">smtp_tls_security_level</a> 11066(default: empty)</b></DT><DD> 11067 11068<p> The default SMTP TLS security level for the Postfix SMTP client; 11069when a non-empty value is specified, this overrides the obsolete 11070parameters <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>, <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a>, and <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a>. 11071</p> 11072 11073<p> Specify one of the following security levels: </p> 11074 11075<dl> 11076 11077<dt><b>none</b></dt> <dd> TLS will not be used unless enabled for specific 11078destinations via <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>. </dd> 11079 11080<dt><b>may</b></dt> 11081<dd> Opportunistic TLS. Use TLS if this is supported by the remote 11082SMTP server, otherwise use plaintext. Since 11083sending in the clear is acceptable, demanding stronger than default TLS 11084security merely reduces inter-operability. 11085The "<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a>" and "<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a>" (Postfix ≥ 2.6) 11086configuration parameters provide control over the protocols and 11087cipher grade used with opportunistic TLS. With earlier releases the 11088opportunistic TLS cipher grade is always "export" and no protocols 11089are disabled. 11090When TLS handshakes fail, the connection is retried with TLS disabled. 11091This allows mail delivery to sites with non-interoperable TLS 11092implementations. </dd> 11093 11094<dt><b>encrypt</b></dt> <dd>Mandatory TLS encryption. Since a minimum 11095level of security is intended, it is reasonable to be specific about 11096sufficiently secure protocol versions and ciphers. At this security level 11097and higher, the <a href="postconf.5.html">main.cf</a> parameters <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> and 11098<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> specify the TLS protocols and minimum 11099cipher grade which the administrator considers secure enough for 11100mandatory encrypted sessions. This security level is not an appropriate 11101default for systems delivering mail to the Internet. </dd> 11102 11103<dt><b>fingerprint</b></dt> <dd>Certificate fingerprint 11104verification. Available with Postfix 2.5 and later. At this security 11105level, there are no trusted certificate authorities. The certificate 11106trust chain, expiration date, ... are not checked. Instead, 11107the <b><a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a></b> parameter lists 11108the valid "fingerprints" of the server certificate. The digest 11109algorithm used to calculate the fingerprint is selected by the 11110<b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a></b> parameter. </dd> 11111 11112<dt><b>verify</b></dt> <dd>Mandatory TLS verification. At this security 11113level, DNS MX lookups are trusted to be secure enough, and the name 11114verified in the server certificate is usually obtained indirectly 11115via unauthenticated DNS MX lookups. The <a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> 11116parameter controls how the server name is verified. In practice explicit 11117control over matching is more common at the "secure" level, described 11118below. This security level is not an appropriate default for systems 11119delivering mail to the Internet. </dd> 11120 11121<dt><b>secure</b></dt> <dd>Secure-channel TLS. At this security level, 11122DNS MX lookups, though potentially used to determine the candidate 11123next-hop gateway IP addresses, are <b>not</b> trusted to be secure enough 11124for TLS peername verification. Instead, the default name verified in 11125the server certificate is obtained from the next-hop domain as specified 11126in the <a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> configuration parameter. The default 11127matching rule is that a server certificate matches when its name is equal 11128to or is a sub-domain of the nexthop domain. This security level is not 11129an appropriate default for systems delivering mail to the Internet. </dd> 11130 11131</dl> 11132 11133<p> 11134Examples: 11135</p> 11136 11137<pre> 11138# No TLS. Formerly: <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>=no and <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a>=no. 11139<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = none 11140</pre> 11141 11142<pre> 11143# Opportunistic TLS. 11144<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = may 11145# Postfix ≥ 2.6: 11146# Do not tweak opportunistic ciphers or protocol unless it is essential 11147# to do so (if a security vulnerability is found in the SSL library that 11148# can be mitigated by disabling a particular protocol or raising the 11149# cipher grade from "export" to "low" or "medium"). 11150<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = export 11151<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2 11152</pre> 11153 11154<pre> 11155# Mandatory (high-grade) TLS encryption. 11156<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = encrypt 11157<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high 11158</pre> 11159 11160<pre> 11161# Mandatory TLS verification of hostname or nexthop domain. 11162<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = verify 11163<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high 11164<a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> = hostname, nexthop, dot-nexthop 11165</pre> 11166 11167<pre> 11168# Secure channel TLS with exact nexthop name match. 11169<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = secure 11170<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = TLSv1 11171<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high 11172<a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> = nexthop 11173</pre> 11174 11175<pre> 11176# Certificate fingerprint verification (Postfix ≥ 2.5). 11177# The CA-less "fingerprint" security level only scales to a limited 11178# number of destinations. As a global default rather than a per-site 11179# setting, this is practical when mail for all recipients is sent 11180# to a central mail hub. 11181<a href="postconf.5.html#relayhost">relayhost</a> = [mailhub.example.com] 11182<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = fingerprint 11183<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 11184<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high 11185<a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> = 11186 3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 11187 EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 11188</pre> 11189 11190<p> This feature is available in Postfix 2.3 and later. </p> 11191 11192 11193</DD> 11194 11195<DT><b><a name="smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> 11196(default: empty)</b></DT><DD> 11197 11198<p> Name of the file containing the optional Postfix SMTP client 11199TLS session cache. Specify a database type that supports enumeration, 11200such as <b>btree</b> or <b>sdbm</b>; there is no need to support 11201concurrent access. The file is created if it does not exist. The <a href="smtp.8.html">smtp(8)</a> 11202daemon does not use this parameter directly, rather the cache is 11203implemented indirectly in the <a href="tlsmgr.8.html">tlsmgr(8)</a> daemon. This means that 11204per-smtp-instance <a href="master.5.html">master.cf</a> overrides of this parameter are not effective. 11205Note, that each of the cache databases supported by <a href="tlsmgr.8.html">tlsmgr(8)</a> daemon: 11206$<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a>, $<a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> 11207(and with Postfix 2.3 and later $<a href="postconf.5.html#lmtp_tls_session_cache_database">lmtp_tls_session_cache_database</a>), needs to 11208be stored separately. It is not at this time possible to store multiple 11209caches in a single database. </p> 11210 11211<p> Note: <b>dbm</b> databases are not suitable. TLS 11212session objects are too large. </p> 11213 11214<p> As of version 2.5, Postfix no longer uses root privileges when 11215opening this file. The file should now be stored under the Postfix-owned 11216<a href="postconf.5.html#data_directory">data_directory</a>. As a migration aid, an attempt to open the file 11217under a non-Postfix directory is redirected to the Postfix-owned 11218<a href="postconf.5.html#data_directory">data_directory</a>, and a warning is logged. </p> 11219 11220<p> Example: </p> 11221 11222<pre> 11223<a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> = btree:/var/db/postfix/smtp_scache 11224</pre> 11225 11226<p> This feature is available in Postfix 2.2 and later. </p> 11227 11228 11229</DD> 11230 11231<DT><b><a name="smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> 11232(default: 3600s)</b></DT><DD> 11233 11234<p> The expiration time of Postfix SMTP client TLS session cache 11235information. A cache cleanup is performed periodically 11236every $<a href="postconf.5.html#smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> seconds. As with 11237$<a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a>, this parameter is implemented in the 11238<a href="tlsmgr.8.html">tlsmgr(8)</a> daemon and therefore per-smtp-instance <a href="master.5.html">master.cf</a> overrides 11239are not possible. </p> 11240 11241<p> This feature is available in Postfix 2.2 and later. </p> 11242 11243 11244</DD> 11245 11246<DT><b><a name="smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> 11247(default: hostname)</b></DT><DD> 11248 11249<p> The server certificate peername verification method for the 11250"verify" TLS security level. In a "verify" TLS policy table 11251($<a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) entry the optional "match" attribute 11252overrides this <a href="postconf.5.html">main.cf</a> setting. </p> 11253 11254<p> This parameter specifies one or more patterns or strategies separated 11255by commas, whitespace or colons. In the policy table the only valid 11256separator is the colon character. </p> 11257 11258<p> Patterns specify domain names, or domain name suffixes: </p> 11259 11260<dl> 11261 11262<dt><i>example.com</i></dt> <dd> Match the <i>example.com</i> domain, 11263i.e. one of the names the server certificate must be <i>example.com</i>, 11264upper and lower case distinctions are ignored. </dd> 11265 11266<dt><i>.example.com</i></dt> 11267<dd> Match subdomains of the <i>example.com</i> domain, i.e. match 11268a name in the server certificate that consists of a non-zero number of 11269labels followed by a <i>.example.com</i> suffix. Case distinctions are 11270ignored.</dd> 11271 11272</dl> 11273 11274<p> Strategies specify a transformation from the next-hop domain 11275to the expected name in the server certificate: </p> 11276 11277<dl> 11278 11279<dt>nexthop</dt> 11280<dd> Match against the next-hop domain, which is either the recipient 11281domain, or the transport next-hop configured for the domain stripped of 11282any optional socket type prefix, enclosing square brackets and trailing 11283port. When MX lookups are not suppressed, this is the original nexthop 11284domain prior to the MX lookup, not the result of the MX lookup. For 11285LMTP delivery via UNIX-domain sockets, the verified next-hop name is 11286$<a href="postconf.5.html#myhostname">myhostname</a>. This strategy is suitable for use with the "secure" 11287policy. Case is ignored.</dd> 11288 11289<dt>dot-nexthop</dt> 11290<dd> As above, but match server certificate names that are subdomains 11291of the next-hop domain. Case is ignored.</dd> 11292 11293<dt>hostname</dt> <dd> Match against the hostname of the server, often 11294obtained via an unauthenticated DNS MX lookup. For LMTP delivery via 11295UNIX-domain sockets, the verified name is $<a href="postconf.5.html#myhostname">myhostname</a>. This matches 11296the verification strategy of the "MUST" keyword in the obsolete 11297<a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> table, and is suitable for use with the "verify" 11298security level. When the next-hop name is enclosed in square brackets 11299to suppress MX lookups, the "hostname" strategy is the same as the 11300"nexthop" strategy. Case is ignored.</dd> 11301 11302</dl> 11303 11304<p> 11305Sample <a href="postconf.5.html">main.cf</a> setting: 11306</p> 11307 11308<pre> 11309<a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> = hostname, nexthop, dot-nexthop 11310</pre> 11311 11312<p> 11313Sample policy table override: 11314</p> 11315 11316<pre> 11317example.com verify match=hostname:nexthop 11318.example.com verify match=example.com:.example.com:hostname 11319</pre> 11320 11321<p> This feature is available in Postfix 2.3 and later. </p> 11322 11323 11324</DD> 11325 11326<DT><b><a name="smtp_use_tls">smtp_use_tls</a> 11327(default: no)</b></DT><DD> 11328 11329<p> Opportunistic mode: use TLS when a remote SMTP server announces 11330STARTTLS support, otherwise send the mail in the clear. Beware: 11331some SMTP servers offer STARTTLS even if it is not configured. With 11332Postfix < 2.3, if the TLS handshake fails, and no other server is 11333available, delivery is deferred and mail stays in the queue. If this 11334is a concern for you, use the <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> feature instead. </p> 11335 11336<p> This feature is available in Postfix 2.2 and later. With 11337Postfix 2.3 and later use <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> instead. </p> 11338 11339 11340</DD> 11341 11342<DT><b><a name="smtp_xforward_timeout">smtp_xforward_timeout</a> 11343(default: 300s)</b></DT><DD> 11344 11345<p> 11346The SMTP client time limit for sending the XFORWARD command, and 11347for receiving the server response. 11348</p> 11349 11350<p> 11351Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 11352The default time unit is s (seconds). 11353</p> 11354 11355<p> 11356This feature is available in Postfix 2.1 and later. 11357</p> 11358 11359 11360</DD> 11361 11362<DT><b><a name="smtpd_authorized_verp_clients">smtpd_authorized_verp_clients</a> 11363(default: $<a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a>)</b></DT><DD> 11364 11365<p> What SMTP clients are allowed to specify the XVERP command. 11366This command requests that mail be delivered one recipient at a 11367time with a per recipient return address. </p> 11368 11369<p> By default, no clients are allowed to specify XVERP. </p> 11370 11371<p> This parameter was renamed with Postfix version 2.1. The default value 11372is backwards compatible with Postfix version 2.0. </p> 11373 11374<p> Specify a list of network/netmask patterns, separated by commas 11375and/or whitespace. The mask specifies the number of bits in the 11376network part of a host address. You can also specify hostnames or 11377.domain names (the initial dot causes the domain to match any name 11378below it), "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns. A "/file/name" 11379pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table 11380is matched when a table entry matches a lookup string (the lookup 11381result is ignored). Continue long lines by starting the next line 11382with whitespace. Specify "!pattern" to exclude an address or network 11383block from the list. The form "!/file/name" is supported only in 11384Postfix version 2.4 and later. </p> 11385 11386<p> Note: IP version 6 address information must be specified inside 11387<tt>[]</tt> in the <a href="postconf.5.html#smtpd_authorized_verp_clients">smtpd_authorized_verp_clients</a> value, and in 11388files specified with "/file/name". IP version 6 addresses contain 11389the ":" character, and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" 11390pattern. </p> 11391 11392 11393</DD> 11394 11395<DT><b><a name="smtpd_authorized_xclient_hosts">smtpd_authorized_xclient_hosts</a> 11396(default: empty)</b></DT><DD> 11397 11398<p> 11399What SMTP clients are allowed to use the XCLIENT feature. This 11400command overrides SMTP client information that is used for access 11401control. Typical use is for SMTP-based content filters, fetchmail-like 11402programs, or SMTP server access rule testing. See the <a href="XCLIENT_README.html">XCLIENT_README</a> 11403document for details. 11404</p> 11405 11406<p> 11407This feature is available in Postfix 2.1 and later. 11408</p> 11409 11410<p> 11411By default, no clients are allowed to specify XCLIENT. 11412</p> 11413 11414<p> 11415Specify a list of network/netmask patterns, separated by commas 11416and/or whitespace. The mask specifies the number of bits in the 11417network part of a host address. You can also specify hostnames or 11418.domain names (the initial dot causes the domain to match any name 11419below it), "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns. A "/file/name" 11420pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table 11421is matched when a table entry matches a lookup string (the lookup 11422result is ignored). Continue long lines by starting the next line 11423with whitespace. Specify "!pattern" to exclude an address or network 11424block from the list. The form "!/file/name" is supported only in 11425Postfix version 2.4 and later. </p> 11426 11427<p> Note: IP version 6 address information must be specified inside 11428<tt>[]</tt> in the <a href="postconf.5.html#smtpd_authorized_xclient_hosts">smtpd_authorized_xclient_hosts</a> value, and in 11429files specified with "/file/name". IP version 6 addresses contain 11430the ":" character, and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" 11431pattern. </p> 11432 11433 11434</DD> 11435 11436<DT><b><a name="smtpd_authorized_xforward_hosts">smtpd_authorized_xforward_hosts</a> 11437(default: empty)</b></DT><DD> 11438 11439<p> 11440What SMTP clients are allowed to use the XFORWARD feature. This 11441command forwards information that is used to improve logging after 11442SMTP-based content filters. See the <a href="XFORWARD_README.html">XFORWARD_README</a> document for 11443details. 11444</p> 11445 11446<p> 11447This feature is available in Postfix 2.1 and later. 11448</p> 11449 11450<p> 11451By default, no clients are allowed to specify XFORWARD. 11452</p> 11453 11454<p> 11455Specify a list of network/netmask patterns, separated by commas 11456and/or whitespace. The mask specifies the number of bits in the 11457network part of a host address. You can also specify hostnames or 11458.domain names (the initial dot causes the domain to match any name 11459below it), "/file/name" or "<a href="DATABASE_README.html">type:table</a>" patterns. A "/file/name" 11460pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table 11461is matched when a table entry matches a lookup string (the lookup 11462result is ignored). Continue long lines by starting the next line 11463with whitespace. Specify "!pattern" to exclude an address or network 11464block from the list. The form "!/file/name" is supported only in 11465Postfix version 2.4 and later. </p> 11466 11467<p> Note: IP version 6 address information must be specified inside 11468<tt>[]</tt> in the <a href="postconf.5.html#smtpd_authorized_xforward_hosts">smtpd_authorized_xforward_hosts</a> value, and in 11469files specified with "/file/name". IP version 6 addresses contain 11470the ":" character, and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" 11471pattern. </p> 11472 11473 11474</DD> 11475 11476<DT><b><a name="smtpd_banner">smtpd_banner</a> 11477(default: $<a href="postconf.5.html#myhostname">myhostname</a> ESMTP $<a href="postconf.5.html#mail_name">mail_name</a>)</b></DT><DD> 11478 11479<p> 11480The text that follows the 220 status code in the SMTP greeting 11481banner. Some people like to see the mail version advertised. By 11482default, Postfix shows no version. 11483</p> 11484 11485<p> 11486You MUST specify $<a href="postconf.5.html#myhostname">myhostname</a> at the start of the text. This is 11487required by the SMTP protocol. 11488</p> 11489 11490<p> 11491Example: 11492</p> 11493 11494<pre> 11495<a href="postconf.5.html#smtpd_banner">smtpd_banner</a> = $<a href="postconf.5.html#myhostname">myhostname</a> ESMTP $<a href="postconf.5.html#mail_name">mail_name</a> ($<a href="postconf.5.html#mail_version">mail_version</a>) 11496</pre> 11497 11498 11499</DD> 11500 11501<DT><b><a name="smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a> 11502(default: 50)</b></DT><DD> 11503 11504<p> 11505How many simultaneous connections any client is allowed to 11506make to this service. By default, the limit is set to half 11507the default process limit value. 11508</p> 11509 11510<p> 11511To disable this feature, specify a limit of 0. 11512</p> 11513 11514<p> 11515WARNING: The purpose of this feature is to limit abuse. It must 11516not be used to regulate legitimate mail traffic. 11517</p> 11518 11519<p> 11520This feature is available in Postfix 2.2 and later. 11521</p> 11522 11523 11524</DD> 11525 11526<DT><b><a name="smtpd_client_connection_rate_limit">smtpd_client_connection_rate_limit</a> 11527(default: 0)</b></DT><DD> 11528 11529<p> 11530The maximal number of connection attempts any client is allowed to 11531make to this service per time unit. The time unit is specified 11532with the <a href="postconf.5.html#anvil_rate_time_unit">anvil_rate_time_unit</a> configuration parameter. 11533</p> 11534 11535<p> 11536By default, a client can make as many connections per time unit as 11537Postfix can accept. 11538</p> 11539 11540<p> 11541To disable this feature, specify a limit of 0. 11542</p> 11543 11544<p> 11545WARNING: The purpose of this feature is to limit abuse. It must 11546not be used to regulate legitimate mail traffic. 11547</p> 11548 11549<p> 11550This feature is available in Postfix 2.2 and later. 11551</p> 11552 11553<p> 11554Example: 11555</p> 11556 11557<pre> 11558<a href="postconf.5.html#smtpd_client_connection_rate_limit">smtpd_client_connection_rate_limit</a> = 1000 11559</pre> 11560 11561 11562</DD> 11563 11564<DT><b><a name="smtpd_client_event_limit_exceptions">smtpd_client_event_limit_exceptions</a> 11565(default: $<a href="postconf.5.html#mynetworks">mynetworks</a>)</b></DT><DD> 11566 11567<p> 11568Clients that are excluded from smtpd_client_*_count/rate_limit 11569restrictions. See the <a href="postconf.5.html#mynetworks">mynetworks</a> parameter 11570description for the parameter value syntax. 11571</p> 11572 11573<p> 11574By default, clients in trusted networks are excluded. Specify a 11575list of network blocks, hostnames or .domain names (the initial 11576dot causes the domain to match any name below it). 11577</p> 11578 11579<p> Note: IP version 6 address information must be specified inside 11580<tt>[]</tt> in the <a href="postconf.5.html#smtpd_client_event_limit_exceptions">smtpd_client_event_limit_exceptions</a> value, and 11581in files specified with "/file/name". IP version 6 addresses 11582contain the ":" character, and would otherwise be confused with a 11583"<a href="DATABASE_README.html">type:table</a>" pattern. </p> 11584 11585<p> 11586This feature is available in Postfix 2.2 and later. 11587</p> 11588 11589 11590</DD> 11591 11592<DT><b><a name="smtpd_client_message_rate_limit">smtpd_client_message_rate_limit</a> 11593(default: 0)</b></DT><DD> 11594 11595<p> 11596The maximal number of message delivery requests that any client is 11597allowed to make to this service per time unit, regardless of whether 11598or not Postfix actually accepts those messages. The time unit is 11599specified with the <a href="postconf.5.html#anvil_rate_time_unit">anvil_rate_time_unit</a> configuration parameter. 11600</p> 11601 11602<p> 11603By default, a client can send as many message delivery requests 11604per time unit as Postfix can accept. 11605</p> 11606 11607<p> 11608To disable this feature, specify a limit of 0. 11609</p> 11610 11611<p> 11612WARNING: The purpose of this feature is to limit abuse. It must 11613not be used to regulate legitimate mail traffic. 11614</p> 11615 11616<p> 11617This feature is available in Postfix 2.2 and later. 11618</p> 11619 11620<p> 11621Example: 11622</p> 11623 11624<pre> 11625<a href="postconf.5.html#smtpd_client_message_rate_limit">smtpd_client_message_rate_limit</a> = 1000 11626</pre> 11627 11628 11629</DD> 11630 11631<DT><b><a name="smtpd_client_new_tls_session_rate_limit">smtpd_client_new_tls_session_rate_limit</a> 11632(default: 0)</b></DT><DD> 11633 11634<p> 11635The maximal number of new (i.e., uncached) TLS sessions that a 11636remote SMTP client is allowed to negotiate with this service per 11637time unit. The time unit is specified with the <a href="postconf.5.html#anvil_rate_time_unit">anvil_rate_time_unit</a> 11638configuration parameter. 11639</p> 11640 11641<p> 11642By default, a remote SMTP client can negotiate as many new TLS 11643sessions per time unit as Postfix can accept. 11644</p> 11645 11646<p> 11647To disable this feature, specify a limit of 0. Otherwise, specify 11648a limit that is at least the per-client concurrent session limit, 11649or else legitimate client sessions may be rejected. 11650</p> 11651 11652<p> 11653WARNING: The purpose of this feature is to limit abuse. It must 11654not be used to regulate legitimate mail traffic. 11655</p> 11656 11657<p> 11658This feature is available in Postfix 2.3 and later. 11659</p> 11660 11661<p> 11662Example: 11663</p> 11664 11665<pre> 11666<a href="postconf.5.html#smtpd_client_new_tls_session_rate_limit">smtpd_client_new_tls_session_rate_limit</a> = 100 11667</pre> 11668 11669 11670</DD> 11671 11672<DT><b><a name="smtpd_client_port_logging">smtpd_client_port_logging</a> 11673(default: no)</b></DT><DD> 11674 11675<p> Enable logging of the remote SMTP client port in addition to 11676the hostname and IP address. The logging format is "host[address]:port". 11677</p> 11678 11679<p> This feature is available in Postfix 2.5 and later. </p> 11680 11681 11682</DD> 11683 11684<DT><b><a name="smtpd_client_recipient_rate_limit">smtpd_client_recipient_rate_limit</a> 11685(default: 0)</b></DT><DD> 11686 11687<p> 11688The maximal number of recipient addresses that any client is allowed 11689to send to this service per time unit, regardless of whether or not 11690Postfix actually accepts those recipients. The time unit is specified 11691with the <a href="postconf.5.html#anvil_rate_time_unit">anvil_rate_time_unit</a> configuration parameter. 11692</p> 11693 11694<p> 11695By default, a client can send as many recipient addresses per time 11696unit as Postfix can accept. 11697</p> 11698 11699<p> 11700To disable this feature, specify a limit of 0. 11701</p> 11702 11703<p> 11704WARNING: The purpose of this feature is to limit abuse. It must 11705not be used to regulate legitimate mail traffic. 11706</p> 11707 11708<p> 11709This feature is available in Postfix 2.2 and later. 11710</p> 11711 11712<p> 11713Example: 11714</p> 11715 11716<pre> 11717<a href="postconf.5.html#smtpd_client_recipient_rate_limit">smtpd_client_recipient_rate_limit</a> = 1000 11718</pre> 11719 11720 11721</DD> 11722 11723<DT><b><a name="smtpd_client_restrictions">smtpd_client_restrictions</a> 11724(default: empty)</b></DT><DD> 11725 11726<p> 11727Optional SMTP server access restrictions in the context of a client 11728SMTP connection request. 11729See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 11730restriction lists" for a discussion of evaluation context and time. 11731</p> 11732 11733<p> 11734The default is to allow all connection requests. 11735</p> 11736 11737<p> 11738Specify a list of restrictions, separated by commas and/or whitespace. 11739Continue long lines by starting the next line with whitespace. 11740Restrictions are applied in the order as specified; the first 11741restriction that matches wins. 11742</p> 11743 11744<p> 11745The following restrictions are specific to client hostname or 11746client network address information. 11747</p> 11748 11749<dl> 11750 11751<dt><b><a name="check_ccert_access">check_ccert_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11752 11753<dd> Use the client certificate fingerprint as lookup key for the 11754specified <a href="access.5.html">access(5)</a> database; with Postfix version 2.2, also require that 11755the SMTP client certificate is verified successfully. 11756The fingerprint digest algorithm is configurable via the 11757<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> parameter (hard-coded as md5 prior to 11758Postfix version 2.5). This feature is available with Postfix version 117592.2 and later. </dd> 11760 11761<dt><b><a name="check_client_access">check_client_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11762 11763<dd>Search the specified access database for the client hostname, 11764parent domains, client IP address, or networks obtained by stripping 11765least significant octets. See the <a href="access.5.html">access(5)</a> manual page for details. </dd> 11766 11767<dt><b><a name="check_client_mx_access">check_client_mx_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11768 11769<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MX hosts for the 11770client hostname, and execute the corresponding action. Note: a result 11771of "OK" is not allowed for safety reasons. Instead, use DUNNO in order 11772to exclude specific hosts from blacklists. This feature is available 11773in Postfix 2.7 and later. </dd> 11774 11775<dt><b><a name="check_client_ns_access">check_client_ns_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11776 11777<dd>Search the specified <a href="access.5.html">access(5)</a> database for the DNS servers for 11778the client hostname, and execute the corresponding action. Note: a 11779result of "OK" is not allowed for safety reasons. Instead, use DUNNO 11780in order to exclude specific hosts from blacklists. This feature is 11781available in Postfix 2.7 and later. </dd> 11782 11783<dt><b><a name="check_reverse_client_hostname_access">check_reverse_client_hostname_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11784 11785<dd>Search the specified access database for the unverified reverse 11786client hostname, parent domains, client IP address, or networks 11787obtained by stripping least significant octets. See the <a href="access.5.html">access(5)</a> 11788manual page for details. Note: a result of "OK" is not allowed for 11789safety reasons. Instead, use DUNNO in order to exclude specific 11790hosts from blacklists. This feature is available in Postfix 2.6 11791and later.</dd> 11792 11793<dt><b><a name="check_reverse_client_hostname_mx_access">check_reverse_client_hostname_mx_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11794 11795<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MX hosts for the 11796unverified reverse client hostname, and execute the corresponding 11797action. Note: a result of "OK" is not allowed for safety reasons. 11798Instead, use DUNNO in order to exclude specific hosts from blacklists. 11799This feature is available in Postfix 2.7 and later. </dd> 11800 11801<dt><b><a name="check_reverse_client_hostname_ns_access">check_reverse_client_hostname_ns_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 11802 11803<dd>Search the specified <a href="access.5.html">access(5)</a> database for the DNS servers for 11804the unverified reverse client hostname, and execute the corresponding 11805action. Note: a result of "OK" is not allowed for safety reasons. 11806Instead, use DUNNO in order to exclude specific hosts from blacklists. 11807This feature is available in Postfix 2.7 and later. </dd> 11808 11809<dt><b><a name="permit_inet_interfaces">permit_inet_interfaces</a></b></dt> 11810 11811<dd>Permit the request when the client IP address matches 11812$<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>. </dd> 11813 11814<dt><b><a name="permit_mynetworks">permit_mynetworks</a></b></dt> 11815 11816<dd>Permit the request when the client IP address matches any 11817network or network address listed in $<a href="postconf.5.html#mynetworks">mynetworks</a>. </dd> 11818 11819<dt><b><a name="permit_sasl_authenticated">permit_sasl_authenticated</a></b></dt> 11820 11821<dd> Permit the request when the client is successfully 11822authenticated via the <a href="http://tools.ietf.org/html/rfc4954">RFC 4954</a> (AUTH) protocol. </dd> 11823 11824<dt><b><a name="permit_tls_all_clientcerts">permit_tls_all_clientcerts</a></b></dt> 11825 11826<dd> Permit the request when the remote SMTP client certificate is 11827verified successfully. This option must be used only if a special 11828CA issues the certificates and only this CA is listed as trusted 11829CA. Otherwise, clients with a third-party certificate would also 11830be allowed to relay. Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = no" when the 11831trusted CA is specified with <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> or <a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a>, 11832to prevent Postfix from appending the system-supplied default CAs. 11833This feature is available with Postfix version 2.2.</dd> 11834 11835<dt><b><a name="permit_tls_clientcerts">permit_tls_clientcerts</a></b></dt> 11836 11837<dd>Permit the request when the remote SMTP client certificate 11838fingerprint is listed in $<a href="postconf.5.html#relay_clientcerts">relay_clientcerts</a>. 11839The fingerprint digest algorithm is configurable via the 11840<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> parameter (hard-coded as md5 prior to 11841Postfix version 2.5). This feature is available with Postfix version 118422.2. </dd> 11843 11844<dt><b><a name="reject_rbl_client">reject_rbl_client <i>rbl_domain=d.d.d.d</i></a></b></dt> 11845 11846<dd>Reject the request when the reversed client network address is 11847listed with the A record "<i>d.d.d.d</i>" under <i>rbl_domain</i> 11848(Postfix version 2.1 and later only). Each "<i>d</i>" is a number, 11849or a pattern inside "[]" that contains one or more ";"-separated 11850numbers or number..number ranges (Postfix version 2.8 and later). 11851If no "<i>=d.d.d.d</i>" is specified, reject the request when the 11852reversed client network address is listed with any A record under 11853<i>rbl_domain</i>. <br> 11854The <a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> parameter specifies the response code for 11855rejected requests (default: 554), the <a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> parameter 11856specifies the default server reply, and the <a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> parameter 11857specifies tables with server replies indexed by <i>rbl_domain</i>. 11858This feature is available in Postfix 2.0 and later. </dd> 11859 11860<dt><b><a name="permit_dnswl_client">permit_dnswl_client <i>dnswl_domain=d.d.d.d</i></a></b></dt> 11861 11862<dd>Accept the request when the reversed client network address is 11863listed with the A record "<i>d.d.d.d</i>" under <i>dnswl_domain</i>. 11864Each "<i>d</i>" is a number, or a pattern inside "[]" that contains 11865one or more ";"-separated numbers or number..number ranges. 11866If no "<i>=d.d.d.d</i>" is specified, accept the request when the 11867reversed client network address is listed with any A record under 11868<i>dnswl_domain</i>. <br> For safety, <a href="postconf.5.html#permit_dnswl_client">permit_dnswl_client</a> is silently 11869ignored when it would override <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a>. The 11870result is DEFER_IF_REJECT when whitelist lookup fails. This feature 11871is available in Postfix 2.8 and later. </dd> 11872 11873<dt><b><a name="reject_rhsbl_client">reject_rhsbl_client <i>rbl_domain=d.d.d.d</i></a></b></dt> 11874 11875<dd>Reject the request when the client hostname is listed with the 11876A record "<i>d.d.d.d</i>" under <i>rbl_domain</i> (Postfix version 118772.1 and later only). Each "<i>d</i>" is a number, or a pattern 11878inside "[]" that contains one or more ";"-separated numbers or 11879number..number ranges (Postfix version 2.8 and later). If no 11880"<i>=d.d.d.d</i>" is specified, reject the request when the client 11881hostname is listed with 11882any A record under <i>rbl_domain</i>. See the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a> 11883description above for additional RBL related configuration parameters. 11884This feature is available in Postfix 2.0 and later; with Postfix 11885version 2.8 and later, <a href="postconf.5.html#reject_rhsbl_reverse_client">reject_rhsbl_reverse_client</a> will usually 11886produce better results. </dd> 11887 11888<dt><b><a name="permit_rhswl_client">permit_rhswl_client <i>rhswl_domain=d.d.d.d</i></a></b></dt> 11889 11890<dd>Accept the request when the client hostname is listed with the 11891A record "<i>d.d.d.d</i>" under <i>rhswl_domain</i>. Each "<i>d</i>" 11892is a number, or a pattern inside "[]" that contains one or more 11893";"-separated numbers or number..number ranges. If no 11894"<i>=d.d.d.d</i>" is specified, accept the request when the client 11895hostname is listed with any A record under <i>rhswl_domain</i>. 11896<br> Caution: client name whitelisting is fragile, since the client 11897name lookup can fail due to temporary outages. Client name 11898whitelisting should be used only to reduce false positives in e.g. 11899DNS-based blocklists, and not for making access rule exceptions. 11900<br> For safety, <a href="postconf.5.html#permit_rhswl_client">permit_rhswl_client</a> is silently ignored when it 11901would override <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a>. The result is DEFER_IF_REJECT 11902when whitelist lookup fails. This feature is available in Postfix 119032.8 and later. </dd> 11904 11905<dt><b><a name="reject_rhsbl_reverse_client">reject_rhsbl_reverse_client <i>rbl_domain=d.d.d.d</i></a></b></dt> 11906 11907<dd>Reject the request when the unverified reverse client hostname 11908is listed with the A record "<i>d.d.d.d</i>" under <i>rbl_domain</i>. 11909Each "<i>d</i>" is a number, or a pattern inside "[]" that contains 11910one or more ";"-separated numbers or number..number ranges. 11911If no "<i>=d.d.d.d</i>" is specified, reject the request when the 11912unverified reverse client hostname is listed with any A record under 11913<i>rbl_domain</i>. See the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a> description above for 11914additional RBL related configuration parameters. This feature is 11915available in Postfix 2.8 and later. </dd> 11916 11917<dt><b><a name="reject_unknown_client_hostname">reject_unknown_client_hostname</a></b> (with Postfix < 2.3: reject_unknown_client)</dt> 11918 11919<dd>Reject the request when 1) the client IP address->name mapping 11920fails, 2) the name->address mapping fails, or 3) the name->address 11921mapping does not match the client IP address. <br> This is a 11922stronger restriction than the <a href="postconf.5.html#reject_unknown_reverse_client_hostname">reject_unknown_reverse_client_hostname</a> 11923feature, which triggers only under condition 1) above. <br> The 11924<a href="postconf.5.html#unknown_client_reject_code">unknown_client_reject_code</a> parameter specifies the response code 11925for rejected requests (default: 450). The reply is always 450 in 11926case the address->name or name->address lookup failed due to 11927a temporary problem. </dd> 11928 11929<dt><b><a name="reject_unknown_reverse_client_hostname">reject_unknown_reverse_client_hostname</a></b></dt> 11930 11931<dd>Reject the request when the client IP address has no address->name 11932mapping. <br> This is a weaker restriction than the 11933<a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> feature, which requires not only 11934that the address->name and name->address mappings exist, but 11935also that the two mappings reproduce the client IP address. <br> 11936The <a href="postconf.5.html#unknown_client_reject_code">unknown_client_reject_code</a> parameter specifies the response 11937code for rejected requests (default: 450). The reply is always 450 11938in case the address->name lookup failed due to a temporary 11939problem. <br> This feature is available in Postfix 2.3 and 11940later. </dd> 11941 11942</dl> 11943 11944<p> 11945In addition, you can use any of the following <a name="generic"> 11946generic</a> restrictions. These restrictions are applicable in 11947any SMTP command context. 11948</p> 11949 11950<dl> 11951 11952<dt><b><a name="check_policy_service">check_policy_service <i>servername</i></a></b></dt> 11953 11954<dd>Query the specified policy server. See the <a href="SMTPD_POLICY_README.html">SMTPD_POLICY_README</a> 11955document for details. This feature is available in Postfix 2.1 11956and later. </dd> 11957 11958<dt><b><a name="defer">defer</a></b></dt> 11959 11960<dd>Defer the request. The client is told to try again later. This 11961restriction is useful at the end of a restriction list, to make 11962the default policy explicit. <br> The <a href="postconf.5.html#defer_code">defer_code</a> parameter specifies 11963the SMTP server reply code (default: 450).</dd> 11964 11965<dt><b><a name="defer_if_permit">defer_if_permit</a></b></dt> 11966 11967<dd>Defer the request if some later restriction would result in an 11968explicit or implicit PERMIT action. This is useful when a blacklisting 11969feature fails due to a temporary problem. This feature is available 11970in Postfix version 2.1 and later. </dd> 11971 11972<dt><b><a name="defer_if_reject">defer_if_reject</a></b></dt> 11973 11974<dd>Defer the request if some later restriction would result in a 11975REJECT action. This is useful when a whitelisting feature fails 11976due to a temporary problem. This feature is available in Postfix 11977version 2.1 and later. </dd> 11978 11979<dt><b><a name="permit">permit</a></b></dt> 11980 11981<dd>Permit the request. This restriction is useful at the end of 11982a restriction list, to make the default policy explicit.</dd> 11983 11984<dt><b><a name="reject_multi_recipient_bounce">reject_multi_recipient_bounce</a></b></dt> 11985 11986<dd>Reject the request when the envelope sender is the null address, 11987and the message has multiple envelope recipients. This usage has 11988rare but legitimate applications: under certain conditions, 11989multi-recipient mail that was posted with the DSN option NOTIFY=NEVER 11990may be forwarded with the null sender address. 11991<br> Note: this restriction can only work reliably 11992when used in <a href="postconf.5.html#smtpd_data_restrictions">smtpd_data_restrictions</a> or 11993<a href="postconf.5.html#smtpd_end_of_data_restrictions">smtpd_end_of_data_restrictions</a>, because the total number of 11994recipients is not known at an earlier stage of the SMTP conversation. 11995Use at the RCPT stage will only reject the second etc. recipient. 11996<br> 11997The <a href="postconf.5.html#multi_recipient_bounce_reject_code">multi_recipient_bounce_reject_code</a> parameter specifies the 11998response code for rejected requests (default: 550). This feature 11999is available in Postfix 2.1 and later. </dd> 12000 12001<dt><b><a name="reject_plaintext_session">reject_plaintext_session</a></b></dt> 12002 12003<dd>Reject the request when the connection is not encrypted. This 12004restriction should not be used before the client has had a chance 12005to negotiate encryption with the AUTH or STARTTLS commands. 12006<br> 12007The <a href="postconf.5.html#plaintext_reject_code">plaintext_reject_code</a> parameter specifies the response 12008code for rejected requests (default: 450). This feature is available 12009in Postfix 2.3 and later. </dd> 12010 12011<dt><b><a name="reject_unauth_pipelining">reject_unauth_pipelining</a></b></dt> 12012 12013<dd>Reject the request when the client sends SMTP commands ahead 12014of time where it is not allowed, or when the client sends SMTP 12015commands ahead of time without knowing that Postfix actually supports 12016ESMTP command pipelining. This stops mail from bulk mail software 12017that improperly uses ESMTP command pipelining in order to speed up 12018deliveries. 12019<br> With Postfix 2.6 and later, the SMTP server sets a per-session 12020flag whenever it detects illegal pipelining, including pipelined 12021EHLO or HELO commands. The <a href="postconf.5.html#reject_unauth_pipelining">reject_unauth_pipelining</a> feature simply 12022tests whether the flag was set at any point in time during the 12023session. 12024<br> With older Postfix versions, <a href="postconf.5.html#reject_unauth_pipelining">reject_unauth_pipelining</a> checks 12025the current status of the input read queue, and its usage is not 12026recommended in contexts other than <a href="postconf.5.html#smtpd_data_restrictions">smtpd_data_restrictions</a>. </dd> 12027 12028<dt><b><a name="reject">reject</a></b></dt> 12029 12030<dd>Reject the request. This restriction is useful at the end of 12031a restriction list, to make the default policy explicit. The 12032<a href="postconf.5.html#reject_code">reject_code</a> configuration parameter specifies the response code for 12033rejected requests (default: 554).</dd> 12034 12035<dt><b><a name="sleep">sleep <i>seconds</i></a></b></dt> 12036 12037<dd>Pause for the specified number of seconds and proceed with 12038the next restriction in the list, if any. This may stop zombie 12039mail when used as: 12040<pre> 12041/etc/postfix/<a href="postconf.5.html">main.cf</a>: 12042 <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> = 12043 sleep 1, <a href="postconf.5.html#reject_unauth_pipelining">reject_unauth_pipelining</a> 12044 <a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> = no 12045</pre> 12046This feature is available in Postfix 2.3. </dd> 12047 12048<dt><b><a name="warn_if_reject">warn_if_reject</a></b></dt> 12049 12050<dd>Change the meaning of the next restriction, so that it logs 12051a warning instead of rejecting a request (look for logfile records 12052that contain "reject_warning"). This is useful for testing new 12053restrictions in a "live" environment without risking unnecessary 12054loss of mail. </dd> 12055 12056</dl> 12057 12058<p> 12059Other restrictions that are valid in this context: 12060</p> 12061 12062<ul> 12063 12064<li> SMTP command specific restrictions that are described under 12065the <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>, <a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> or 12066<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> parameters. When helo, sender or 12067recipient restrictions are listed under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, 12068they have effect only with "<a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> = yes", so that 12069$<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> is evaluated at the time of the RCPT TO 12070command. 12071 12072</ul> 12073 12074<p> 12075Example: 12076</p> 12077 12078<pre> 12079<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> 12080</pre> 12081 12082 12083</DD> 12084 12085<DT><b><a name="smtpd_command_filter">smtpd_command_filter</a> 12086(default: empty)</b></DT><DD> 12087 12088<p> A mechanism to transform commands from remote SMTP clients. 12089This is a last-resort tool to work around client commands that break 12090inter-operability with the Postfix SMTP server. Other uses involve 12091fault injection to test Postfix's handling of invalid commands. 12092</p> 12093 12094<p> Specify the name of a "<a href="DATABASE_README.html">type:table</a>" lookup table. The search 12095string is the SMTP command as received from the remote SMTP client, 12096except that initial whitespace and the trailing <CR><LF> 12097are removed. The result value is executed by the Postfix SMTP 12098server. </p> 12099 12100<p> There is no need to use <a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a> for the following 12101cases: </p> 12102 12103<ul> 12104 12105<li> <p> Use "<a href="postconf.5.html#resolve_numeric_domain">resolve_numeric_domain</a> = yes" to accept 12106"<i>user@ipaddress</i>". </p> 12107 12108<li> <p> Postfix already accepts the correct form 12109"<i>user@[ipaddress]</i>". Use <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> or <a href="postconf.5.html#canonical_maps">canonical_maps</a> 12110to translate these into domain names if necessary. </p> 12111 12112<li> <p> Use "<a href="postconf.5.html#strict_rfc821_envelopes">strict_rfc821_envelopes</a> = no" to accept "RCPT TO:<<i>User 12113Name <user@example.com>></i>". Postfix will ignore the "<i>User 12114Name</i>" part and deliver to the <i><user@example.com></i> address. 12115</p> 12116 12117</ul> 12118 12119<p> Examples of problems that can be solved with the <a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a> 12120feature: </p> 12121 12122<pre> 12123/etc/postfix/<a href="postconf.5.html">main.cf</a>: 12124 <a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a> = <a href="pcre_table.5.html">pcre</a>:/etc/postfix/command_filter 12125</pre> 12126 12127<pre> 12128/etc/postfix/command_filter: 12129 # Work around clients that send malformed HELO commands. 12130 /^HELO\s*$/ HELO domain.invalid 12131</pre> 12132 12133<pre> 12134 # Work around clients that send empty lines. 12135 /^\s*$/ NOOP 12136</pre> 12137 12138<pre> 12139 # Work around clients that send RCPT TO:<'user@domain'>. 12140 # WARNING: do not lose the parameters that follow the address. 12141 /^RCPT\s+TO:\s*<'([^[:space:]]+)'>(.*)/ RCPT TO:<$1>$2 12142</pre> 12143 12144<pre> 12145 # Bounce-never mail sink. Use <a href="postconf.5.html#notify_classes">notify_classes</a>=bounce,resource,software 12146 # to send bounced mail to the postmaster (with message body removed). 12147 /^(RCPT\s+TO:.*?)\bNOTIFY=\S+\b(.*)/ $1 NOTIFY=NEVER $2 12148 /^(RCPT\s+TO:.*)/ $1 NOTIFY=NEVER 12149</pre> 12150 12151<p> This feature is available in Postfix 2.7. </p> 12152 12153 12154</DD> 12155 12156<DT><b><a name="smtpd_data_restrictions">smtpd_data_restrictions</a> 12157(default: empty)</b></DT><DD> 12158 12159<p> 12160Optional access restrictions that the Postfix SMTP server applies 12161in the context of the SMTP DATA command. 12162See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 12163restriction lists" for a discussion of evaluation context and time. 12164</p> 12165 12166<p> 12167This feature is available in Postfix 2.0 and later. 12168</p> 12169 12170<p> 12171Specify a list of restrictions, separated by commas and/or whitespace. 12172Continue long lines by starting the next line with whitespace. 12173Restrictions are applied in the order as specified; the first 12174restriction that matches wins. 12175</p> 12176 12177<p> 12178The following restrictions are valid in this context: 12179</p> 12180 12181<ul> 12182 12183<li><a href="#generic">Generic</a> restrictions that can be used 12184in any SMTP command context, described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 12185 12186<li>SMTP command specific restrictions described under 12187<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>, 12188<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> or <a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>. 12189 12190<li>However, no recipient information is available in the case of 12191multi-recipient mail. Acting on only one recipient would be misleading, 12192because any decision will affect all recipients equally. Acting on 12193all recipients would require a possibly very large amount of memory, 12194and would also be misleading for the reasons mentioned before. 12195 12196</ul> 12197 12198<p> 12199Examples: 12200</p> 12201 12202<pre> 12203<a href="postconf.5.html#smtpd_data_restrictions">smtpd_data_restrictions</a> = <a href="postconf.5.html#reject_unauth_pipelining">reject_unauth_pipelining</a> 12204<a href="postconf.5.html#smtpd_data_restrictions">smtpd_data_restrictions</a> = <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipient_bounce</a> 12205</pre> 12206 12207 12208</DD> 12209 12210<DT><b><a name="smtpd_delay_open_until_valid_rcpt">smtpd_delay_open_until_valid_rcpt</a> 12211(default: yes)</b></DT><DD> 12212 12213<p> Postpone the start of an SMTP mail transaction until a valid 12214RCPT TO command is received. Specify "no" to create a mail transaction 12215as soon as the SMTP server receives a valid MAIL FROM command. </p> 12216 12217<p> With sites that reject lots of mail, the default setting reduces 12218the use of 12219disk, CPU and memory resources. The downside is that rejected 12220recipients are logged with NOQUEUE instead of a mail transaction 12221ID. This complicates the logfile analysis of multi-recipient mail. 12222</p> 12223 12224<p> This feature is available in Postfix 2.3 and later. </p> 12225 12226 12227</DD> 12228 12229<DT><b><a name="smtpd_delay_reject">smtpd_delay_reject</a> 12230(default: yes)</b></DT><DD> 12231 12232<p> 12233Wait until the RCPT TO command before evaluating 12234$<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> and 12235$<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>, or wait until the ETRN command before 12236evaluating $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>. 12237</p> 12238 12239<p> 12240This feature is turned on by default because some clients apparently 12241mis-behave when the Postfix SMTP server rejects commands before 12242RCPT TO. 12243</p> 12244 12245<p> 12246The default setting has one major benefit: it allows Postfix to log 12247recipient address information when rejecting a client name/address 12248or sender address, so that it is possible to find out whose mail 12249is being rejected. 12250</p> 12251 12252 12253</DD> 12254 12255<DT><b><a name="smtpd_discard_ehlo_keyword_address_maps">smtpd_discard_ehlo_keyword_address_maps</a> 12256(default: empty)</b></DT><DD> 12257 12258<p> Lookup tables, indexed by the remote SMTP client address, with 12259case insensitive lists of EHLO keywords (pipelining, starttls, auth, 12260etc.) that the SMTP server will not send in the EHLO response to a 12261remote SMTP client. See <a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_keywords</a> for details. 12262The table is not searched by hostname for robustness reasons. </p> 12263 12264<p> This feature is available in Postfix 2.2 and later. </p> 12265 12266 12267</DD> 12268 12269<DT><b><a name="smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_keywords</a> 12270(default: empty)</b></DT><DD> 12271 12272<p> A case insensitive list of EHLO keywords (pipelining, starttls, 12273auth, etc.) that the SMTP server will not send in the EHLO response 12274to a remote SMTP client. </p> 12275 12276<p> This feature is available in Postfix 2.2 and later. </p> 12277 12278<p> Notes: </p> 12279 12280<ul> 12281 12282<li> <p> Specify the <b>silent-discard</b> pseudo keyword to prevent 12283this action from being logged. </p> 12284 12285<li> <p> Use the <a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_discard_ehlo_keyword_address_maps</a> feature 12286to discard EHLO keywords selectively. </p> 12287 12288</ul> 12289 12290 12291</DD> 12292 12293<DT><b><a name="smtpd_end_of_data_restrictions">smtpd_end_of_data_restrictions</a> 12294(default: empty)</b></DT><DD> 12295 12296<p> Optional access restrictions that the Postfix SMTP server 12297applies in the context of the SMTP END-OF-DATA command. 12298See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 12299restriction lists" for a discussion of evaluation context and time. 12300</p> 12301 12302<p> This feature is available in Postfix 2.2 and later. </p> 12303 12304<p> See <a href="postconf.5.html#smtpd_data_restrictions">smtpd_data_restrictions</a> for details and limitations. </p> 12305 12306 12307</DD> 12308 12309<DT><b><a name="smtpd_enforce_tls">smtpd_enforce_tls</a> 12310(default: no)</b></DT><DD> 12311 12312<p> Mandatory TLS: announce STARTTLS support to SMTP clients, 12313and require that clients use TLS encryption. According to <a href="http://tools.ietf.org/html/rfc2487">RFC 2487</a> 12314this MUST NOT be applied in case of a publicly-referenced SMTP 12315server. This option is off by default and should be used only on 12316dedicated servers. </p> 12317 12318<p> Note 1: "<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a> = yes" implies "<a href="postconf.5.html#smtpd_tls_auth_only">smtpd_tls_auth_only</a> = yes". </p> 12319 12320<p> Note 2: when invoked via "<b>sendmail -bs</b>", Postfix will never offer 12321STARTTLS due to insufficient privileges to access the server private 12322key. This is intended behavior. </p> 12323 12324<p> This feature is available in Postfix 2.2 and later. With 12325Postfix 2.3 and later use <a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> instead. </p> 12326 12327 12328</DD> 12329 12330<DT><b><a name="smtpd_error_sleep_time">smtpd_error_sleep_time</a> 12331(default: 1s)</b></DT><DD> 12332 12333<p>With Postfix version 2.1 and later: the SMTP server response delay after 12334a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> errors, and 12335fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without delivering mail. 12336</p> 12337 12338<p>With Postfix version 2.0 and earlier: the SMTP server delay before 12339sending a reject (4xx or 5xx) response, when the client has made 12340fewer than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> errors without delivering 12341mail. </p> 12342 12343 12344</DD> 12345 12346<DT><b><a name="smtpd_etrn_restrictions">smtpd_etrn_restrictions</a> 12347(default: empty)</b></DT><DD> 12348 12349<p> 12350Optional SMTP server access restrictions in the context of a client 12351ETRN request. 12352See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 12353restriction lists" for a discussion of evaluation context and time. 12354</p> 12355 12356<p> 12357The Postfix ETRN implementation accepts only destinations that are 12358eligible for the Postfix "fast flush" service. See the <a href="ETRN_README.html">ETRN_README</a> 12359file for details. 12360</p> 12361 12362<p> 12363Specify a list of restrictions, separated by commas and/or whitespace. 12364Continue long lines by starting the next line with whitespace. 12365Restrictions are applied in the order as specified; the first 12366restriction that matches wins. 12367</p> 12368 12369<p> 12370The following restrictions are specific to the domain name information 12371received with the ETRN command. 12372</p> 12373 12374<dl> 12375 12376<dt><b><a name="check_etrn_access">check_etrn_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12377 12378<dd>Search the specified access database for the ETRN domain name 12379or its parent domains. See the <a href="access.5.html">access(5)</a> manual page for details. 12380</dd> 12381 12382</dl> 12383 12384<p> 12385Other restrictions that are valid in this context: 12386</p> 12387 12388<ul> 12389 12390<li><a href="#generic">Generic</a> restrictions that can be used 12391in any SMTP command context, described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 12392 12393<li>SMTP command specific restrictions described under 12394<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>. 12395 12396</ul> 12397 12398<p> 12399Example: 12400</p> 12401 12402<pre> 12403<a href="postconf.5.html#smtpd_etrn_restrictions">smtpd_etrn_restrictions</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, reject 12404</pre> 12405 12406 12407</DD> 12408 12409<DT><b><a name="smtpd_expansion_filter">smtpd_expansion_filter</a> 12410(default: see "postconf -d" output)</b></DT><DD> 12411 12412<p> 12413What characters are allowed in $name expansions of RBL reply 12414templates. Characters not in the allowed set are replaced by "_". 12415Use C like escapes to specify special characters such as whitespace. 12416</p> 12417 12418<p> 12419This parameter is not subjected to $parameter expansion. 12420</p> 12421 12422<p> 12423This feature is available in Postfix 2.0 and later. 12424</p> 12425 12426 12427</DD> 12428 12429<DT><b><a name="smtpd_forbidden_commands">smtpd_forbidden_commands</a> 12430(default: CONNECT, GET, POST)</b></DT><DD> 12431 12432<p> 12433List of commands that cause the Postfix SMTP server to immediately 12434terminate the session with a 221 code. This can be used to disconnect 12435clients that obviously attempt to abuse the system. In addition to the 12436commands listed in this parameter, commands that follow the "Label:" 12437format of message headers will also cause a disconnect. 12438</p> 12439 12440<p> 12441This feature is available in Postfix 2.2 and later. 12442</p> 12443 12444 12445</DD> 12446 12447<DT><b><a name="smtpd_hard_error_limit">smtpd_hard_error_limit</a> 12448(default: normal: 20, overload: 1)</b></DT><DD> 12449 12450<p> 12451The maximal number of errors a remote SMTP client is allowed to 12452make without delivering mail. The Postfix SMTP server disconnects 12453when the limit is exceeded. Normally the default limit is 20, but 12454it changes under overload to just 1. With Postfix 2.5 and earlier, 12455the SMTP server always allows up to 20 errors by default. 12456 12457</p> 12458 12459 12460</DD> 12461 12462<DT><b><a name="smtpd_helo_required">smtpd_helo_required</a> 12463(default: no)</b></DT><DD> 12464 12465<p> 12466Require that a remote SMTP client introduces itself with the HELO 12467or EHLO command before sending the MAIL command or other commands 12468that require EHLO negotiation. 12469</p> 12470 12471<p> 12472Example: 12473</p> 12474 12475<pre> 12476<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes 12477</pre> 12478 12479 12480</DD> 12481 12482<DT><b><a name="smtpd_helo_restrictions">smtpd_helo_restrictions</a> 12483(default: empty)</b></DT><DD> 12484 12485<p> 12486Optional restrictions that the Postfix SMTP server applies in the 12487context of the SMTP HELO command. 12488See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 12489restriction lists" for a discussion of evaluation context and time. 12490</p> 12491 12492<p> 12493The default is to permit everything. 12494</p> 12495 12496<p> Note: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce this 12497restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can 12498simply skip <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> by not sending HELO or EHLO). 12499</p> 12500 12501<p> 12502Specify a list of restrictions, separated by commas and/or whitespace. 12503Continue long lines by starting the next line with whitespace. 12504Restrictions are applied in the order as specified; the first 12505restriction that matches wins. 12506</p> 12507 12508<p> 12509The following restrictions are specific to the hostname information 12510received with the HELO or EHLO command. 12511</p> 12512 12513<dl> 12514 12515<dt><b><a name="check_helo_access">check_helo_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12516 12517<dd>Search the specified <a href="access.5.html">access(5)</a> database for the HELO or EHLO 12518hostname or parent domains, and execute the corresponding action. 12519Note: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce this 12520restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can 12521simply skip <a href="postconf.5.html#check_helo_access">check_helo_access</a> by not sending HELO or EHLO). </dd> 12522 12523<dt><b><a name="check_helo_mx_access">check_helo_mx_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12524 12525<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MX hosts for 12526the HELO or EHLO hostname, and execute the corresponding action. 12527Note 1: a result of "OK" is not allowed for safety reasons. Instead, 12528use DUNNO in order to exclude specific hosts from blacklists. Note 125292: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce this 12530restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can 12531simply skip <a href="postconf.5.html#check_helo_mx_access">check_helo_mx_access</a> by not sending HELO or EHLO). This 12532feature is available in Postfix 2.1 and later. 12533</dd> 12534 12535<dt><b><a name="check_helo_ns_access">check_helo_ns_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12536 12537<dd>Search the specified <a href="access.5.html">access(5)</a> database for the DNS servers 12538for the HELO or EHLO hostname, and execute the corresponding action. 12539Note 1: a result of "OK" is not allowed for safety reasons. Instead, 12540use DUNNO in order to exclude specific hosts from blacklists. Note 125412: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce this 12542restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can 12543simply skip <a href="postconf.5.html#check_helo_ns_access">check_helo_ns_access</a> by not sending HELO or EHLO). This 12544feature is available in Postfix 2.1 and later. 12545</dd> 12546 12547<dt><b><a name="reject_invalid_helo_hostname">reject_invalid_helo_hostname</a></b> (with Postfix < 2.3: reject_invalid_hostname)</dt> 12548 12549<dd>Reject the request when the HELO or EHLO hostname syntax is 12550invalid. Note: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce 12551this restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can simply 12552skip <a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> by not sending HELO or EHLO). 12553<br> The <a href="postconf.5.html#invalid_hostname_reject_code">invalid_hostname_reject_code</a> specifies the response code 12554for rejected requests (default: 501).</dd> 12555 12556<dt><b><a name="reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a></b> (with Postfix < 2.3: reject_non_fqdn_hostname)</dt> 12557 12558<dd>Reject the request when the HELO or EHLO hostname is not in 12559fully-qualified domain form, as required by the RFC. Note: specify 12560"<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully enforce this restriction 12561(without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a client can simply skip 12562<a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a> by not sending HELO or EHLO). <br> 12563The <a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> parameter specifies the response code for 12564rejected requests (default: 504).</dd> 12565 12566<dt><b><a name="reject_rhsbl_helo">reject_rhsbl_helo <i>rbl_domain=d.d.d.d</i></a></b></dt> 12567 12568<dd>Reject the request when the HELO or EHLO hostname hostname is 12569listed with the A record "<i>d.d.d.d</i>" under <i>rbl_domain</i> 12570(Postfix version 2.1 and later only). Each "<i>d</i>" is a number, 12571or a pattern inside "[]" that contains one or more ";"-separated 12572numbers or number..number ranges (Postfix version 2.8 and later). 12573If no "<i>=d.d.d.d</i>" is 12574specified, reject the request when the HELO or EHLO hostname is 12575listed with any A record under <i>rbl_domain</i>. See the 12576<a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a> description for additional RBL related configuration 12577parameters. Note: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully 12578enforce this restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a 12579client can simply skip <a href="postconf.5.html#reject_rhsbl_helo">reject_rhsbl_helo</a> by not sending HELO or 12580EHLO). This feature is available in Postfix 2.0 12581and later. </dd> 12582 12583<dt><b><a name="reject_unknown_helo_hostname">reject_unknown_helo_hostname</a></b> (with Postfix < 2.3: reject_unknown_hostname)</dt> 12584 12585<dd>Reject the request when the HELO or EHLO hostname has no DNS A 12586or MX record. <br> The <a href="postconf.5.html#unknown_hostname_reject_code">unknown_hostname_reject_code</a> parameter 12587specifies the numerical response code for rejected requests (default: 12588450). <br> The <a href="postconf.5.html#unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a> parameter 12589specifies the action after a temporary DNS error (default: 12590<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>). Note: specify "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes" to fully 12591enforce this restriction (without "<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> = yes", a 12592client can simply skip <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> by not sending 12593HELO or EHLO). </dd> 12594 12595</dl> 12596 12597<p> 12598Other restrictions that are valid in this context: 12599</p> 12600 12601<ul> 12602 12603<li> <a href="#generic">Generic</a> restrictions that can be used 12604in any SMTP command context, described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 12605 12606<li> Client hostname or network address specific restrictions 12607described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 12608 12609<li> SMTP command specific restrictions described under 12610<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> or <a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>. When 12611sender or recipient restrictions are listed under <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>, 12612they have effect only with "<a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> = yes", so that 12613$<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> is evaluated at the time of the RCPT TO 12614command. 12615 12616</ul> 12617 12618<p> 12619Examples: 12620</p> 12621 12622<pre> 12623<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> 12624<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> 12625</pre> 12626 12627 12628</DD> 12629 12630<DT><b><a name="smtpd_history_flush_threshold">smtpd_history_flush_threshold</a> 12631(default: 100)</b></DT><DD> 12632 12633<p> 12634The maximal number of lines in the Postfix SMTP server command history 12635before it is flushed upon receipt of EHLO, RSET, or end of DATA. 12636</p> 12637 12638 12639</DD> 12640 12641<DT><b><a name="smtpd_junk_command_limit">smtpd_junk_command_limit</a> 12642(default: normal: 100, overload: 1)</b></DT><DD> 12643 12644<p> 12645The number of junk commands (NOOP, VRFY, ETRN or RSET) that a remote 12646SMTP client can send before the Postfix SMTP server starts to 12647increment the error counter with each junk command. The junk 12648command count is reset after mail is delivered. See also the 12649<a href="postconf.5.html#smtpd_error_sleep_time">smtpd_error_sleep_time</a> and <a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> configuration 12650parameters. Normally the default limit is 100, but it changes under 12651overload to just 1. With Postfix 2.5 and earlier, the SMTP server 12652always allows up to 100 junk commands by default. </p> 12653 12654 12655</DD> 12656 12657<DT><b><a name="smtpd_milters">smtpd_milters</a> 12658(default: empty)</b></DT><DD> 12659 12660<p> A list of Milter (mail filter) applications for new mail that 12661arrives via the Postfix <a href="smtpd.8.html">smtpd(8)</a> server. See the <a href="MILTER_README.html">MILTER_README</a> 12662document for details. </p> 12663 12664<p> This feature is available in Postfix 2.3 and later. </p> 12665 12666 12667</DD> 12668 12669<DT><b><a name="smtpd_noop_commands">smtpd_noop_commands</a> 12670(default: empty)</b></DT><DD> 12671 12672<p> 12673List of commands that the Postfix SMTP server replies to with "250 12674Ok", without doing any syntax checks and without changing state. 12675This list overrides any commands built into the Postfix SMTP server. 12676</p> 12677 12678 12679</DD> 12680 12681<DT><b><a name="smtpd_null_access_lookup_key">smtpd_null_access_lookup_key</a> 12682(default: <>)</b></DT><DD> 12683 12684<p> 12685The lookup key to be used in SMTP <a href="access.5.html">access(5)</a> tables instead of the 12686null sender address. 12687</p> 12688 12689 12690</DD> 12691 12692<DT><b><a name="smtpd_peername_lookup">smtpd_peername_lookup</a> 12693(default: yes)</b></DT><DD> 12694 12695<p> Attempt to look up the remote SMTP client hostname, and verify that 12696the name matches the client IP address. A client name is set to 12697"unknown" when it cannot be looked up or verified, or when name 12698lookup is disabled. Turning off name lookup reduces delays due to 12699DNS lookup and increases the maximal inbound delivery rate. </p> 12700 12701<p> This feature is available in Postfix 2.3 and later. </p> 12702 12703 12704</DD> 12705 12706<DT><b><a name="smtpd_policy_service_max_idle">smtpd_policy_service_max_idle</a> 12707(default: 300s)</b></DT><DD> 12708 12709<p> 12710The time after which an idle SMTPD policy service connection is 12711closed. 12712</p> 12713 12714<p> 12715This feature is available in Postfix 2.1 and later. 12716</p> 12717 12718 12719</DD> 12720 12721<DT><b><a name="smtpd_policy_service_max_ttl">smtpd_policy_service_max_ttl</a> 12722(default: 1000s)</b></DT><DD> 12723 12724<p> 12725The time after which an active SMTPD policy service connection is 12726closed. 12727</p> 12728 12729<p> 12730This feature is available in Postfix 2.1 and later. 12731</p> 12732 12733 12734</DD> 12735 12736<DT><b><a name="smtpd_policy_service_timeout">smtpd_policy_service_timeout</a> 12737(default: 100s)</b></DT><DD> 12738 12739<p> 12740The time limit for connecting to, writing to or receiving from a 12741delegated SMTPD policy server. 12742</p> 12743 12744<p> 12745This feature is available in Postfix 2.1 and later. 12746</p> 12747 12748 12749</DD> 12750 12751<DT><b><a name="smtpd_proxy_ehlo">smtpd_proxy_ehlo</a> 12752(default: $<a href="postconf.5.html#myhostname">myhostname</a>)</b></DT><DD> 12753 12754<p> 12755How the Postfix SMTP server announces itself to the proxy filter. 12756By default, the Postfix hostname is used. 12757</p> 12758 12759<p> 12760This feature is available in Postfix 2.1 and later. 12761</p> 12762 12763 12764</DD> 12765 12766<DT><b><a name="smtpd_proxy_filter">smtpd_proxy_filter</a> 12767(default: empty)</b></DT><DD> 12768 12769<p> The hostname and TCP port of the mail filtering proxy server. 12770The proxy receives all mail from the Postfix SMTP server, and is 12771supposed to give the result to another Postfix SMTP server process. 12772</p> 12773 12774<p> Specify "host:port" or "inet:host:port" for a TCP endpoint, or 12775"unix:pathname" for a UNIX-domain endpoint. The host can be specified 12776as an IP address or as a symbolic name; no MX lookups are done. 12777When no "host" or "host:" are specified, the local machine is 12778assumed. Pathname interpretation is relative to the Postfix queue 12779directory. </p> 12780 12781<p> This feature is available in Postfix 2.1 and later. </p> 12782 12783<p> The "inet:" and "unix:" prefixes are available in Postfix 2.3 12784and later. </p> 12785 12786 12787</DD> 12788 12789<DT><b><a name="smtpd_proxy_options">smtpd_proxy_options</a> 12790(default: empty)</b></DT><DD> 12791 12792<p> 12793List of options that control how the Postfix SMTP server 12794communicates with a before-queue content filter. Specify zero or 12795more of the following, separated by comma or whitespace. </p> 12796 12797<dl> 12798 12799<dt><b>speed_adjust</b></dt> 12800 12801<dd> <p> Do not connect to a before-queue content filter until an entire 12802message has been received. This reduces the number of simultaneous 12803before-queue content filter processes. </p> 12804 12805<p> NOTE 1: A filter must not <i>selectively</i> reject recipients 12806of a multi-recipient message. Rejecting all recipients is OK, as 12807is accepting all recipients. </p> 12808 12809<p> NOTE 2: This feature increases the minimum amount of free queue 12810space by $<a href="postconf.5.html#message_size_limit">message_size_limit</a>. The extra space is needed to save the 12811message to a temporary file. </p> </dd> 12812 12813</dl> 12814 12815<p> 12816This feature is available in Postfix 2.7 and later. 12817</p> 12818 12819 12820</DD> 12821 12822<DT><b><a name="smtpd_proxy_timeout">smtpd_proxy_timeout</a> 12823(default: 100s)</b></DT><DD> 12824 12825<p> 12826The time limit for connecting to a proxy filter and for sending or 12827receiving information. When a connection fails the client gets a 12828generic error message while more detailed information is logged to 12829the maillog file. 12830</p> 12831 12832<p> 12833Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 12834The default time unit is s (seconds). 12835</p> 12836 12837<p> 12838This feature is available in Postfix 2.1 and later. 12839</p> 12840 12841 12842</DD> 12843 12844<DT><b><a name="smtpd_recipient_limit">smtpd_recipient_limit</a> 12845(default: 1000)</b></DT><DD> 12846 12847<p> 12848The maximal number of recipients that the Postfix SMTP server 12849accepts per message delivery request. 12850</p> 12851 12852 12853</DD> 12854 12855<DT><b><a name="smtpd_recipient_overshoot_limit">smtpd_recipient_overshoot_limit</a> 12856(default: 1000)</b></DT><DD> 12857 12858<p> The number of recipients that a remote SMTP client can send in 12859excess of the limit specified with $<a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a>, before 12860the Postfix SMTP server increments the per-session error count 12861for each excess recipient. </p> 12862 12863 12864</DD> 12865 12866<DT><b><a name="smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> 12867(default: <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a>)</b></DT><DD> 12868 12869<p> 12870The access restrictions that the Postfix SMTP server applies in 12871the context of the RCPT TO command. 12872See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 12873restriction lists" for a discussion of evaluation context and time. 12874</p> 12875 12876<p> 12877By default, the Postfix SMTP server accepts: 12878</p> 12879 12880<ul> 12881 12882<li> Mail from clients whose IP address matches $<a href="postconf.5.html#mynetworks">mynetworks</a>, or: 12883 12884<li> Mail to remote destinations that match $<a href="postconf.5.html#relay_domains">relay_domains</a>, except 12885for addresses that contain sender-specified routing 12886(user@elsewhere@domain), or: 12887 12888<li> Mail to local destinations that match $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 12889or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, or 12890$<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>. 12891 12892</ul> 12893 12894<p> 12895IMPORTANT: If you change this parameter setting, you must specify 12896at least one of the following restrictions. Otherwise Postfix will 12897refuse to receive mail: 12898</p> 12899 12900<blockquote> 12901<pre> 12902reject, defer, <a href="postconf.5.html#defer_if_permit">defer_if_permit</a>, <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> 12903</pre> 12904</blockquote> 12905 12906<p> 12907Specify a list of restrictions, separated by commas and/or whitespace. 12908Continue long lines by starting the next line with whitespace. 12909Restrictions are applied in the order as specified; the first 12910restriction that matches wins. 12911</p> 12912 12913<p> 12914The following restrictions are specific to the recipient address 12915that is received with the RCPT TO command. 12916</p> 12917 12918<dl> 12919 12920<dt><b><a name="check_recipient_access">check_recipient_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12921 12922<dd>Search the specified <a href="access.5.html">access(5)</a> database for the resolved RCPT 12923TO address, domain, parent domains, or localpart@, and execute the 12924corresponding action. </dd> 12925 12926<dt><b><a name="check_recipient_mx_access">check_recipient_mx_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12927 12928<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MX hosts for 12929the RCPT TO domain, and execute the corresponding action. Note: 12930a result of "OK" is not allowed for safety reasons. Instead, use 12931DUNNO in order to exclude specific hosts from blacklists. This 12932feature is available in Postfix 2.1 and later. </dd> 12933 12934<dt><b><a name="check_recipient_ns_access">check_recipient_ns_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 12935 12936<dd>Search the specified <a href="access.5.html">access(5)</a> database for the DNS servers 12937for the RCPT TO domain, and execute the corresponding action. 12938Note: a result of "OK" is not allowed for safety reasons. Instead, 12939use DUNNO in order to exclude specific hosts from blacklists. This 12940feature is available in Postfix 2.1 and later. </dd> 12941 12942<dt><b><a name="permit_auth_destination">permit_auth_destination</a></b></dt> 12943 12944<dd>Permit the request when one of the following is true: 12945 12946<ul> 12947 12948<li> Postfix is mail forwarder: the resolved RCPT TO domain matches 12949$<a href="postconf.5.html#relay_domains">relay_domains</a> or a subdomain thereof, and the address contains no 12950sender-specified routing (user@elsewhere@domain), 12951 12952<li> Postfix is the final destination: the resolved RCPT TO domain 12953matches $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>, $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, 12954$<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, or $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, and the address 12955contains no sender-specified routing (user@elsewhere@domain). 12956 12957</ul></dd> 12958 12959<dt><b><a name="permit_mx_backup">permit_mx_backup</a></b></dt> 12960 12961<dd>Permit the request when the local mail system is backup MX for 12962the RCPT TO domain, or when the domain is an authorized destination 12963(see <a href="postconf.5.html#permit_auth_destination">permit_auth_destination</a> for definition). 12964 12965<ul> 12966 12967<li> Safety: <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> does not accept addresses that have 12968sender-specified routing information (example: user@elsewhere@domain). 12969 12970<li> Safety: <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> can be vulnerable to mis-use when 12971access is not restricted with <a href="postconf.5.html#permit_mx_backup_networks">permit_mx_backup_networks</a>. 12972 12973<li> Safety: as of Postfix version 2.3, <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> no longer 12974accepts the address when the local mail system is primary MX for 12975the recipient domain. Exception: <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> accepts the address 12976when it specifies an authorized destination (see <a href="postconf.5.html#permit_auth_destination">permit_auth_destination</a> 12977for definition). 12978 12979<li> Limitation: mail may be rejected in case of a temporary DNS 12980lookup problem with Postfix prior to version 2.0. 12981 12982</ul></dd> 12983 12984<dt><b><a name="reject_non_fqdn_recipient">reject_non_fqdn_recipient</a></b></dt> 12985 12986<dd>Reject the request when the RCPT TO address is not in 12987fully-qualified domain form, as required by the RFC. <br> The 12988<a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> parameter specifies the response code for 12989rejected requests (default: 504). </dd> 12990 12991<dt><b><a name="reject_rhsbl_recipient">reject_rhsbl_recipient <i>rbl_domain=d.d.d.d</i></a></b></dt> 12992 12993<dd>Reject the request when the RCPT TO domain is listed with the 12994A record "<i>d.d.d.d</i>" under <i>rbl_domain</i> (Postfix version 129952.1 and later only). Each "<i>d</i>" is a number, or a pattern 12996inside "[]" that contains one or more ";"-separated numbers or 12997number..number ranges (Postfix version 2.8 and later). If no 12998"<i>=d.d.d.d</i>" is specified, reject 12999the request when the RCPT TO domain is listed with 13000any A record under <i>rbl_domain</i>. <br> The <a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> 13001parameter specifies the response code for rejected requests (default: 13002554); the <a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> parameter specifies the default server 13003reply; and the <a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> parameter specifies tables with server 13004replies indexed by <i>rbl_domain</i>. This feature is available 13005in Postfix version 2.0 and later.</dd> 13006 13007<dt><b><a name="reject_unauth_destination">reject_unauth_destination</a></b></dt> 13008 13009<dd>Reject the request unless one of the following is true: 13010 13011<ul> 13012 13013<li> Postfix is mail forwarder: the resolved RCPT TO domain matches 13014$<a href="postconf.5.html#relay_domains">relay_domains</a> or a subdomain thereof, and contains no sender-specified 13015routing (user@elsewhere@domain), 13016 13017<li> Postfix is the final destination: the resolved RCPT TO domain 13018matches $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>, $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, 13019$<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, or $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, and contains 13020no sender-specified routing (user@elsewhere@domain). 13021 13022</ul> The <a href="postconf.5.html#relay_domains_reject_code">relay_domains_reject_code</a> parameter specifies the response 13023code for rejected requests (default: 554). </dd> 13024 13025<dt><b><a name="reject_unknown_recipient_domain">reject_unknown_recipient_domain</a></b></dt> 13026 13027<dd>Reject the request when Postfix is not final destination for 13028the recipient domain, and the RCPT TO domain has no DNS A or MX 13029record, or when it has a malformed MX record such as a record with 13030a zero-length MX hostname (Postfix version 2.3 and later). <br> The 13031<a href="postconf.5.html#unknown_address_reject_code">unknown_address_reject_code</a> parameter specifies the numerical 13032response code for rejected requests (default: 450). The response 13033is always 450 in case of a temporary DNS error. <br> The 13034<a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a> parameter specifies the action 13035after a temporary DNS error (default: <a href="postconf.5.html#defer_if_permit">defer_if_permit</a>). </dd> 13036 13037<dt><b><a name="reject_unlisted_recipient">reject_unlisted_recipient</a></b> (with Postfix version 2.0: check_recipient_maps)</dt> 13038 13039<dd> Reject the request when the RCPT TO address is not listed in 13040the list of valid recipients for its domain class. See the 13041<a href="postconf.5.html#smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> parameter description for details. 13042This feature is available in Postfix 2.1 and later.</dd> 13043 13044<dt><b><a name="reject_unverified_recipient">reject_unverified_recipient</a></b></dt> 13045 13046<dd>Reject the request when mail to the RCPT TO address is known 13047to bounce, or when the recipient address destination is not reachable. 13048Address verification information is managed by the <a href="verify.8.html">verify(8)</a> server; 13049see the <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> file for details. <br> The 13050<a href="postconf.5.html#unverified_recipient_reject_code">unverified_recipient_reject_code</a> parameter specifies the numerical 13051response code when an address is known to bounce (default: 450, 13052change into 550 when you are confident that it is safe to do so). 13053<br>The <a href="postconf.5.html#unverified_recipient_defer_code">unverified_recipient_defer_code</a> parameter specifies the 13054numerical response code when an address probe failed due to a 13055temporary problem (default: 450). <br> The 13056<a href="postconf.5.html#unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a> parameter specifies the action 13057after addres probe failure due to a temporary problem (default: 13058<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>). <br> This feature is available in Postfix 2.1 13059and later. </dd> 13060 13061</dl> 13062 13063<p> 13064Other restrictions that are valid in this context: 13065</p> 13066 13067<ul> 13068 13069<li><a href="#generic">Generic</a> restrictions that can be used 13070in any SMTP command context, described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 13071 13072<li>SMTP command specific restrictions described under 13073<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> and 13074<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>. 13075 13076</ul> 13077 13078<p> 13079Example: 13080</p> 13081 13082<pre> 13083<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> 13084</pre> 13085 13086 13087</DD> 13088 13089<DT><b><a name="smtpd_reject_footer">smtpd_reject_footer</a> 13090(default: empty)</b></DT><DD> 13091 13092<p> Optional information that is appended after each SMTP server 130934XX or 5XX response. </p> 13094 13095<p> Example: </p> 13096 13097<pre> 13098/etc/postfix/<a href="postconf.5.html">main.cf</a>: 13099 <a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a> = For assistance, call 800-555-0101. 13100 Please provide the following information in your problem report: 13101 time ($localtime), client ($client_address) and server 13102 ($server_name). 13103</pre> 13104 13105<p> Server response: </p> 13106 13107<pre> 13108 550-5.5.1 <user@example> Recipient address rejected: User unknown 13109 550 5.5.1 For assistance, call 800-555-0101. Please provide the 13110 following information in your problem report: time (Jan 4 15:42:00), 13111 client (192.168.1.248) and server (mail1.example.com). 13112</pre> 13113 13114<p> Note: the above text is meant to make it easier to find the 13115Postfix logfile records for a failed SMTP session. The text itself 13116is not logged to the Postfix SMTP server's maillog file. </p> 13117 13118<p> Be sure to keep the text as short as possible. Long text may 13119be truncated before it is logged to the remote SMTP client's maillog 13120file, or before it is returned to the sender in a delivery status 13121notification. </p> 13122 13123<p> This feature supports a limited number of $name attributes in 13124the footer text. These are replaced by their current value for the 13125SMTP session: </p> 13126 13127<dl> 13128 13129<dt> <b>client_address</b> </dt> <dd> The Client IP address that 13130is logged in the maillog file. </dd> 13131 13132<dt> <b>client_port</b> </dt> <dd> The client TCP port that is 13133logged in the maillog file. </dd> 13134 13135<dt> <b>localtime</b> </dt> <dd> The server local time (Mmm dd 13136hh:mm:ss) that is logged in the maillog file. </dd> 13137 13138<dt> <b>server_name</b> </dt> <dd> The server's <a href="postconf.5.html#myhostname">myhostname</a> value. 13139This attribute is made available for sites with multiple MTAs 13140(perhaps behind a load-balancer), where the server name can help 13141the server support team to quickly find the right log files. </dd> 13142 13143</dl> 13144 13145<p> Notes: </p> 13146 13147<ul> 13148 13149<li> <p> NOT SUPPORTED are other attributes such as sender, recipient, 13150or <a href="postconf.5.html">main.cf</a> parameters. </p> 13151 13152<li> <p> For safety reasons, text that does not match 13153$<a href="postconf.5.html#smtpd_expansion_filter">smtpd_expansion_filter</a> is censored. </p> 13154 13155</ul> 13156 13157<p> This feature supports the two-character sequence \n as a request 13158for a line break in the footer text. Postfix automatically inserts 13159after each line break the three-digit SMTP reply code (and optional 13160enhanced status code) from the original Postfix reject message. 13161</p> 13162 13163<p> This feature is available in Postfix 2.8 and later. </p> 13164 13165 13166</DD> 13167 13168<DT><b><a name="smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> 13169(default: yes)</b></DT><DD> 13170 13171<p> 13172Request that the Postfix SMTP server rejects mail for unknown 13173recipient addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_recipient">reject_unlisted_recipient</a> 13174access restriction is specified. This prevents the Postfix queue 13175from filling up with undeliverable MAILER-DAEMON messages. 13176</p> 13177 13178<p> An address is always considered "known" when it matches a 13179<a href="virtual.5.html">virtual(5)</a> alias or a <a href="canonical.5.html">canonical(5)</a> mapping. 13180 13181<ul> 13182 13183<li> The recipient domain matches $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 13184or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, but the recipient is not listed in 13185$<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a>, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> is not null. 13186 13187<li> The recipient domain matches $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> but the 13188recipient is not listed in $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>. 13189 13190<li> The recipient domain matches $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> but the 13191recipient is not listed in $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>, and $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> 13192is not null. 13193 13194<li> The recipient domain matches $<a href="postconf.5.html#relay_domains">relay_domains</a> but the recipient 13195is not listed in $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a>, and $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> 13196is not null. 13197 13198</ul> 13199 13200<p> 13201This feature is available in Postfix 2.1 and later. 13202</p> 13203 13204 13205</DD> 13206 13207<DT><b><a name="smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> 13208(default: no)</b></DT><DD> 13209 13210<p> Request that the Postfix SMTP server rejects mail from unknown 13211sender addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a> 13212access restriction is specified. This can slow down an explosion 13213of forged mail from worms or viruses. </p> 13214 13215<p> An address is always considered "known" when it matches a 13216<a href="virtual.5.html">virtual(5)</a> alias or a <a href="canonical.5.html">canonical(5)</a> mapping. 13217 13218<ul> 13219 13220<li> The sender domain matches $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or 13221$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>, but the sender is not listed in 13222$<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a>, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> is not null. 13223 13224<li> The sender domain matches $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> but the sender 13225is not listed in $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>. 13226 13227<li> The sender domain matches $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> but the 13228sender is not listed in $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>, and $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> 13229is not null. 13230 13231<li> The sender domain matches $<a href="postconf.5.html#relay_domains">relay_domains</a> but the sender is 13232not listed in $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a>, and $<a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> is 13233not null. 13234 13235</ul> 13236 13237<p> 13238This feature is available in Postfix 2.1 and later. 13239</p> 13240 13241 13242</DD> 13243 13244<DT><b><a name="smtpd_restriction_classes">smtpd_restriction_classes</a> 13245(default: empty)</b></DT><DD> 13246 13247<p> 13248User-defined aliases for groups of access restrictions. The aliases 13249can be specified in <a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> etc., and on the 13250right-hand side of a Postfix <a href="access.5.html">access(5)</a> table. 13251</p> 13252 13253<p> 13254One major application is for implementing per-recipient UCE control. 13255See the <a href="RESTRICTION_CLASS_README.html">RESTRICTION_CLASS_README</a> document for other examples. 13256</p> 13257 13258 13259</DD> 13260 13261<DT><b><a name="smtpd_sasl_application_name">smtpd_sasl_application_name</a> 13262(default: smtpd)</b></DT><DD> 13263 13264<p> 13265The application name that the Postfix SMTP server uses for SASL 13266server initialization. This 13267controls the name of the SASL configuration file. The default value 13268is <b>smtpd</b>, corresponding to a SASL configuration file named 13269<b>smtpd.conf</b>. 13270</p> 13271 13272<p> 13273This feature is available in Postfix 2.1 and 2.2. With Postfix 2.3 13274it was renamed to <a href="postconf.5.html#smtpd_sasl_path">smtpd_sasl_path</a>. 13275</p> 13276 13277 13278</DD> 13279 13280<DT><b><a name="smtpd_sasl_auth_enable">smtpd_sasl_auth_enable</a> 13281(default: no)</b></DT><DD> 13282 13283<p> 13284Enable SASL authentication in the Postfix SMTP server. By default, 13285the Postfix SMTP server does not use authentication. 13286</p> 13287 13288<p> 13289If a remote SMTP client is authenticated, the <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a> 13290access restriction can be used to permit relay access, like this: 13291</p> 13292 13293<blockquote> 13294<pre> 13295<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> = 13296 <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>, ... 13297</pre> 13298</blockquote> 13299 13300<p> To reject all SMTP connections from unauthenticated clients, 13301specify "<a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> = yes" (which is the default) and use: 13302</p> 13303 13304<blockquote> 13305<pre> 13306<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> = <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>, reject 13307</pre> 13308</blockquote> 13309 13310<p> 13311See the <a href="SASL_README.html">SASL_README</a> file for SASL configuration and operation details. 13312</p> 13313 13314 13315</DD> 13316 13317<DT><b><a name="smtpd_sasl_authenticated_header">smtpd_sasl_authenticated_header</a> 13318(default: no)</b></DT><DD> 13319 13320<p> Report the SASL authenticated user name in the <a href="smtpd.8.html">smtpd(8)</a> Received 13321message header. </p> 13322 13323<p> This feature is available in Postfix 2.3 and later. </p> 13324 13325 13326</DD> 13327 13328<DT><b><a name="smtpd_sasl_exceptions_networks">smtpd_sasl_exceptions_networks</a> 13329(default: empty)</b></DT><DD> 13330 13331<p> 13332What remote SMTP clients the Postfix SMTP server will not offer 13333AUTH support to. 13334</p> 13335 13336<p> 13337Some clients (Netscape 4 at least) have a bug that causes them to 13338require a login and password whenever AUTH is offered, whether it's 13339necessary or not. To work around this, specify, for example, 13340$<a href="postconf.5.html#mynetworks">mynetworks</a> to prevent Postfix from offering AUTH to local clients. 13341</p> 13342 13343<p> 13344Specify a list of network/netmask patterns, separated by commas 13345and/or whitespace. The mask specifies the number of bits in the 13346network part of a host address. You can also "/file/name" or 13347"<a href="DATABASE_README.html">type:table</a>" patterns. A "/file/name" pattern is replaced by its 13348contents; a "<a href="DATABASE_README.html">type:table</a>" lookup table is matched when a table entry 13349matches a lookup string (the lookup result is ignored). Continue 13350long lines by starting the next line with whitespace. Specify 13351"!pattern" to exclude an address or network block from the list. 13352The form "!/file/name" is supported only in Postfix version 2.4 and 13353later. </p> 13354 13355<p> Note: IP version 6 address information must be specified inside 13356<tt>[]</tt> in the <a href="postconf.5.html#smtpd_sasl_exceptions_networks">smtpd_sasl_exceptions_networks</a> value, and in 13357files specified with "/file/name". IP version 6 addresses contain 13358the ":" character, and would otherwise be confused with a "<a href="DATABASE_README.html">type:table</a>" 13359pattern. </p> 13360 13361<p> 13362Example: 13363</p> 13364 13365<pre> 13366<a href="postconf.5.html#smtpd_sasl_exceptions_networks">smtpd_sasl_exceptions_networks</a> = $<a href="postconf.5.html#mynetworks">mynetworks</a> 13367</pre> 13368 13369<p> 13370This feature is available in Postfix 2.1 and later. 13371</p> 13372 13373 13374</DD> 13375 13376<DT><b><a name="smtpd_sasl_local_domain">smtpd_sasl_local_domain</a> 13377(default: empty)</b></DT><DD> 13378 13379<p> 13380The name of the Postfix SMTP server's local SASL authentication 13381realm. 13382</p> 13383 13384<p> 13385By default, the local authentication realm name is the null string. 13386</p> 13387 13388<p> 13389Examples: 13390</p> 13391 13392<pre> 13393<a href="postconf.5.html#smtpd_sasl_local_domain">smtpd_sasl_local_domain</a> = $<a href="postconf.5.html#mydomain">mydomain</a> 13394<a href="postconf.5.html#smtpd_sasl_local_domain">smtpd_sasl_local_domain</a> = $<a href="postconf.5.html#myhostname">myhostname</a> 13395</pre> 13396 13397 13398</DD> 13399 13400<DT><b><a name="smtpd_sasl_path">smtpd_sasl_path</a> 13401(default: smtpd)</b></DT><DD> 13402 13403<p> Implementation-specific information that the Postfix SMTP server 13404passes through to 13405the SASL plug-in implementation that is selected with 13406<b><a href="postconf.5.html#smtpd_sasl_type">smtpd_sasl_type</a></b>. Typically this specifies the name of a 13407configuration file or rendezvous point. </p> 13408 13409<p> This feature is available in Postfix 2.3 and later. In earlier 13410releases it was called <b><a href="postconf.5.html#smtpd_sasl_application_name">smtpd_sasl_application_name</a></b>. </p> 13411 13412 13413</DD> 13414 13415<DT><b><a name="smtpd_sasl_security_options">smtpd_sasl_security_options</a> 13416(default: noanonymous)</b></DT><DD> 13417 13418<p> Postfix SMTP server SASL security options; as of Postfix 2.3 13419the list of available 13420features depends on the SASL server implementation that is selected 13421with <b><a href="postconf.5.html#smtpd_sasl_type">smtpd_sasl_type</a></b>. </p> 13422 13423<p> The following security features are defined for the <b>cyrus</b> 13424server SASL implementation: </p> 13425 13426<p> 13427Restrict what authentication mechanisms the Postfix SMTP server 13428will offer to the client. The list of available authentication 13429mechanisms is system dependent. 13430</p> 13431 13432<p> 13433Specify zero or more of the following: 13434</p> 13435 13436<dl> 13437 13438<dt><b>noplaintext</b></dt> 13439 13440<dd>Disallow methods that use plaintext passwords. </dd> 13441 13442<dt><b>noactive</b></dt> 13443 13444<dd>Disallow methods subject to active (non-dictionary) attack. </dd> 13445 13446<dt><b>nodictionary</b></dt> 13447 13448<dd>Disallow methods subject to passive (dictionary) attack. </dd> 13449 13450<dt><b>noanonymous</b></dt> 13451 13452<dd>Disallow methods that allow anonymous authentication. </dd> 13453 13454<dt><b>forward_secrecy</b></dt> 13455 13456<dd>Only allow methods that support forward secrecy (Dovecot only). 13457</dd> 13458 13459<dt><b>mutual_auth</b></dt> 13460 13461<dd>Only allow methods that provide mutual authentication (not available 13462with Cyrus SASL version 1). </dd> 13463 13464</dl> 13465 13466<p> 13467By default, the Postfix SMTP server accepts plaintext passwords but 13468not anonymous logins. 13469</p> 13470 13471<p> 13472Warning: it appears that clients try authentication methods in the 13473order as advertised by the server (e.g., PLAIN ANONYMOUS CRAM-MD5) 13474which means that if you disable plaintext passwords, clients will 13475log in anonymously, even when they should be able to use CRAM-MD5. 13476So, if you disable plaintext logins, disable anonymous logins too. 13477Postfix treats anonymous login as no authentication. 13478</p> 13479 13480<p> 13481Example: 13482</p> 13483 13484<pre> 13485<a href="postconf.5.html#smtpd_sasl_security_options">smtpd_sasl_security_options</a> = noanonymous, noplaintext 13486</pre> 13487 13488 13489</DD> 13490 13491<DT><b><a name="smtpd_sasl_tls_security_options">smtpd_sasl_tls_security_options</a> 13492(default: $<a href="postconf.5.html#smtpd_sasl_security_options">smtpd_sasl_security_options</a>)</b></DT><DD> 13493 13494<p> The SASL authentication security options that the Postfix SMTP 13495server uses for TLS encrypted SMTP sessions. </p> 13496 13497<p> This feature is available in Postfix 2.2 and later. </p> 13498 13499 13500</DD> 13501 13502<DT><b><a name="smtpd_sasl_type">smtpd_sasl_type</a> 13503(default: cyrus)</b></DT><DD> 13504 13505<p> The SASL plug-in type that the Postfix SMTP server should use 13506for authentication. The available types are listed with the 13507"<b>postconf -a</b>" command. </p> 13508 13509<p> This feature is available in Postfix 2.3 and later. </p> 13510 13511 13512</DD> 13513 13514<DT><b><a name="smtpd_sender_login_maps">smtpd_sender_login_maps</a> 13515(default: empty)</b></DT><DD> 13516 13517<p> 13518Optional lookup table with the SASL login names that own sender 13519(MAIL FROM) addresses. 13520</p> 13521 13522<p> 13523Specify zero or more "<a href="DATABASE_README.html">type:table</a>" lookup tables. With lookups from 13524indexed files such as DB or DBM, or from networked tables such as 13525NIS, LDAP or SQL, the following search operations are done with a 13526sender address of <i>user@domain</i>: </p> 13527 13528<dl> 13529 13530<dt> 1) <i>user@domain</i> </dt> 13531 13532<dd>This table lookup is always done and has the highest precedence. </dd> 13533 13534<dt> 2) <i>user</i> </dt> 13535 13536<dd>This table lookup is done only when the <i>domain</i> part of the 13537sender address matches $<a href="postconf.5.html#myorigin">myorigin</a>, $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> 13538or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. </dd> 13539 13540<dt> 3) <i>@domain</i> </dt> 13541 13542<dd>This table lookup is done last and has the lowest precedence. </dd> 13543 13544</dl> 13545 13546<p> 13547In all cases the result of table lookup must be either "not found" 13548or a list of SASL login names separated by comma and/or whitespace. 13549</p> 13550 13551 13552</DD> 13553 13554<DT><b><a name="smtpd_sender_restrictions">smtpd_sender_restrictions</a> 13555(default: empty)</b></DT><DD> 13556 13557<p> 13558Optional restrictions that the Postfix SMTP server applies in the 13559context of the MAIL FROM command. 13560See <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a>, section "Delayed evaluation of SMTP access 13561restriction lists" for a discussion of evaluation context and time. 13562</p> 13563 13564<p> 13565The default is to permit everything. 13566</p> 13567 13568<p> 13569Specify a list of restrictions, separated by commas and/or whitespace. 13570Continue long lines by starting the next line with whitespace. 13571Restrictions are applied in the order as specified; the first 13572restriction that matches wins. 13573</p> 13574 13575<p> 13576The following restrictions are specific to the sender address 13577received with the MAIL FROM command. 13578</p> 13579 13580<dl> 13581 13582<dt><b><a name="check_sender_access">check_sender_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 13583 13584<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MAIL FROM 13585address, domain, parent domains, or localpart@, and execute the 13586corresponding action. </dd> 13587 13588<dt><b><a name="check_sender_mx_access">check_sender_mx_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 13589 13590<dd>Search the specified <a href="access.5.html">access(5)</a> database for the MX hosts for 13591the MAIL FROM address, and execute the corresponding action. Note: 13592a result of "OK" is not allowed for safety reasons. Instead, use 13593DUNNO in order to exclude specific hosts from blacklists. This 13594feature is available in Postfix 2.1 and later. </dd> 13595 13596<dt><b><a name="check_sender_ns_access">check_sender_ns_access</a> <i><a href="DATABASE_README.html">type:table</a></i></b></dt> 13597 13598<dd>Search the specified <a href="access.5.html">access(5)</a> database for the DNS servers 13599for the MAIL FROM address, and execute the corresponding action. 13600Note: a result of "OK" is not allowed for safety reasons. Instead, 13601use DUNNO in order to exclude specific hosts from blacklists. This 13602feature is available in Postfix 2.1 and later. </dd> 13603 13604<dt><b><a name="reject_authenticated_sender_login_mismatch">reject_authenticated_sender_login_mismatch</a></b></dt> 13605 13606<dd>Enforces the <a href="postconf.5.html#reject_sender_login_mismatch">reject_sender_login_mismatch</a> restriction for 13607authenticated clients only. This feature is available in 13608Postfix version 2.1 and later. </dd> 13609 13610<dt><b><a name="reject_non_fqdn_sender">reject_non_fqdn_sender</a></b></dt> 13611 13612<dd>Reject the request when the MAIL FROM address is not in 13613fully-qualified domain form, as required by the RFC. <br> The 13614<a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> parameter specifies the response code for 13615rejected requests (default: 504). </dd> 13616 13617<dt><b><a name="reject_rhsbl_sender">reject_rhsbl_sender <i>rbl_domain=d.d.d.d</i></a></b></dt> 13618 13619<dd>Reject the request when the MAIL FROM domain is listed with 13620the A record "<i>d.d.d.d</i>" under <i>rbl_domain</i> (Postfix 13621version 2.1 and later only). Each "<i>d</i>" is a number, or a 13622pattern inside "[]" that contains one or more ";"-separated numbers 13623or number..number ranges (Postfix version 2.8 and later). If no 13624"<i>=d.d.d.d</i>" is specified, 13625reject the request when the MAIL FROM domain is 13626listed with any A record under <i>rbl_domain</i>. <br> The 13627<a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> parameter specifies the response code for 13628rejected requests (default: 554); the <a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> parameter 13629specifies the default server reply; and the <a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> parameter 13630specifies tables with server replies indexed by <i>rbl_domain</i>. 13631This feature is available in Postfix 2.0 and later.</dd> 13632 13633<dt><b><a name="reject_sender_login_mismatch">reject_sender_login_mismatch</a></b></dt> 13634 13635<dd>Reject the request when $<a href="postconf.5.html#smtpd_sender_login_maps">smtpd_sender_login_maps</a> specifies an 13636owner for the MAIL FROM address, but the client is not (SASL) logged 13637in as that MAIL FROM address owner; or when the client is (SASL) 13638logged in, but the client login name doesn't own the MAIL FROM 13639address according to $<a href="postconf.5.html#smtpd_sender_login_maps">smtpd_sender_login_maps</a>.</dd> 13640 13641<dt><b><a name="reject_unauthenticated_sender_login_mismatch">reject_unauthenticated_sender_login_mismatch</a></b></dt> 13642 13643<dd>Enforces the <a href="postconf.5.html#reject_sender_login_mismatch">reject_sender_login_mismatch</a> restriction for 13644unauthenticated clients only. This feature is available in 13645Postfix version 2.1 and later. </dd> 13646 13647<dt><b><a name="reject_unknown_sender_domain">reject_unknown_sender_domain</a></b></dt> 13648 13649<dd>Reject the request when Postfix is not final destination for 13650the sender address, and the MAIL FROM address has no DNS A or MX 13651record, or when it has a malformed MX record such as a record with 13652a zero-length MX hostname (Postfix version 2.3 and later). <br> The 13653<a href="postconf.5.html#unknown_address_reject_code">unknown_address_reject_code</a> parameter specifies the numerical 13654response code for rejected requests (default: 450). The response 13655is always 450 in case of a temporary DNS error. <br> The 13656<a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a> parameter specifies the action 13657after a temporary DNS error (default: <a href="postconf.5.html#defer_if_permit">defer_if_permit</a>). </dd> 13658 13659<dt><b><a name="reject_unlisted_sender">reject_unlisted_sender</a></b></dt> 13660 13661<dd>Reject the request when the MAIL FROM address is not listed in 13662the list of valid recipients for its domain class. See the 13663<a href="postconf.5.html#smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> parameter description for details. 13664This feature is available in Postfix 2.1 and later.</dd> 13665 13666<dt><b><a name="reject_unverified_sender">reject_unverified_sender</a></b></dt> 13667 13668<dd>Reject the request when mail to the MAIL FROM address is known to 13669bounce, or when the sender address destination is not reachable. 13670Address verification information is managed by the <a href="verify.8.html">verify(8)</a> server; 13671see the <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> file for details. <br> The 13672<a href="postconf.5.html#unverified_sender_reject_code">unverified_sender_reject_code</a> parameter specifies the numerical 13673response code when an address is known to bounce (default: 450, 13674change into 550 when you are confident that it is safe to do so). 13675<br>The <a href="postconf.5.html#unverified_sender_defer_code">unverified_sender_defer_code</a> specifies the numerical response 13676code when an address address probe failed due to a temporary problem 13677(default: 450). <br> The <a href="postconf.5.html#unverified_sender_tempfail_action">unverified_sender_tempfail_action</a> parameter 13678specifies the action after address probe failure due to a temporary 13679problem (default: <a href="postconf.5.html#defer_if_permit">defer_if_permit</a>). <br> This feature is available 13680in Postfix 2.1 and later. </dd> 13681 13682</dl> 13683 13684<p> 13685Other restrictions that are valid in this context: 13686</p> 13687 13688<ul> 13689 13690<li> <a href="#generic">Generic</a> restrictions that can be used 13691in any SMTP command context, described under <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>. 13692 13693<li> SMTP command specific restrictions described under 13694<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and <a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>. 13695 13696<li> SMTP command specific restrictions described under 13697<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>. When recipient restrictions are listed 13698under <a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>, they have effect only with 13699"<a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> = yes", so that $<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> is 13700evaluated at the time of the RCPT TO command. 13701 13702</ul> 13703 13704<p> 13705Examples: 13706</p> 13707 13708<pre> 13709<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> = <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> 13710<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> = <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>, 13711 <a href="postconf.5.html#check_sender_access">check_sender_access</a> hash:/etc/postfix/access 13712</pre> 13713 13714 13715</DD> 13716 13717<DT><b><a name="smtpd_service_name">smtpd_service_name</a> 13718(default: smtpd)</b></DT><DD> 13719 13720<p> The internal service that <a href="postscreen.8.html">postscreen(8)</a> forwards allowed 13721connections to. In a future version there may be different 13722classes of SMTP service. </p> 13723 13724<p> This feature is available in Postfix 2.8. </p> 13725 13726 13727</DD> 13728 13729<DT><b><a name="smtpd_soft_error_limit">smtpd_soft_error_limit</a> 13730(default: 10)</b></DT><DD> 13731 13732<p> 13733The number of errors a remote SMTP client is allowed to make without 13734delivering mail before the Postfix SMTP server slows down all its 13735responses. 13736</p> 13737 13738<ul> 13739 13740<li><p>With Postfix version 2.1 and later, the Postfix SMTP server 13741delays all responses by $<a href="postconf.5.html#smtpd_error_sleep_time">smtpd_error_sleep_time</a> seconds. </p> 13742 13743<li><p>With Postfix versions 2.0 and earlier, the Postfix SMTP 13744server delays all responses by (number of errors) seconds. </p> 13745 13746</ul> 13747 13748 13749</DD> 13750 13751<DT><b><a name="smtpd_starttls_timeout">smtpd_starttls_timeout</a> 13752(default: see "postconf -d" output)</b></DT><DD> 13753 13754<p> The time limit for Postfix SMTP server write and read operations 13755during TLS startup and shutdown handshake procedures. The current 13756default value is stress-dependent. Before Postfix version 2.8, it 13757was fixed at 300s. </p> 13758 13759<p> This feature is available in Postfix 2.2 and later. </p> 13760 13761 13762</DD> 13763 13764<DT><b><a name="smtpd_timeout">smtpd_timeout</a> 13765(default: normal: 300s, overload: 10s)</b></DT><DD> 13766 13767<p> 13768The time limit for sending a Postfix SMTP server response and for 13769receiving a remote SMTP client request. Normally the default limit 13770is 300s, but it changes under overload to just 10s. With Postfix 137712.5 and earlier, the SMTP server always uses a time limit of 300s 13772by default. 13773</p> 13774 13775<p> 13776Note: if you set SMTP time limits to very large values you may have 13777to update the global <a href="postconf.5.html#ipc_timeout">ipc_timeout</a> parameter. 13778</p> 13779 13780<p> 13781Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 13782The default time unit is s (seconds). 13783</p> 13784 13785 13786</DD> 13787 13788<DT><b><a name="smtpd_tls_CAfile">smtpd_tls_CAfile</a> 13789(default: empty)</b></DT><DD> 13790 13791<p> A file containing (PEM format) CA certificates of root CAs trusted 13792to sign either remote SMTP client certificates or intermediate CA 13793certificates. These are loaded into memory before the <a href="smtpd.8.html">smtpd(8)</a> server 13794enters the chroot jail. If the number of trusted roots is large, consider 13795using <a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> instead, but note that the latter directory must 13796be present in the chroot jail if the <a href="smtpd.8.html">smtpd(8)</a> server is chrooted. This 13797file may also be used to augment the server certificate trust chain, 13798but it is best to include all the required certificates directly in the 13799server certificate file. </p> 13800 13801<p> Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = no" to prevent Postfix from 13802appending the system-supplied default CAs and trusting third-party 13803certificates. </p> 13804 13805<p> By default (see <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>), client certificates are not 13806requested, and <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> should remain empty. If you do make use 13807of client certificates, the distinguished names (DNs) of the certificate 13808authorities listed in <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> are sent to the remote SMTP client 13809in the client certificate request message. MUAs with multiple client 13810certificates may use the list of preferred certificate authorities 13811to select the correct client certificate. You may want to put your 13812"preferred" CA or CAs in this file, and install other trusted CAs in 13813$<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a>. </p> 13814 13815<p> Example: </p> 13816 13817<pre> 13818<a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> = /etc/postfix/CAcert.pem 13819</pre> 13820 13821<p> This feature is available in Postfix 2.2 and later. </p> 13822 13823 13824</DD> 13825 13826<DT><b><a name="smtpd_tls_CApath">smtpd_tls_CApath</a> 13827(default: empty)</b></DT><DD> 13828 13829<p> A directory containing (PEM format) CA certificates of root CAs 13830trusted to sign either remote SMTP client certificates or intermediate CA 13831certificates. Do not forget to create the necessary "hash" links with, 13832for example, "$OPENSSL_HOME/bin/c_rehash /etc/postfix/certs". To use 13833<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> in chroot mode, this directory (or a copy) must be 13834inside the chroot jail. </p> 13835 13836<p> Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = no" to prevent Postfix from 13837appending the system-supplied default CAs and trusting third-party 13838certificates. </p> 13839 13840<p> By default (see <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>), client certificates are 13841not requested, and <a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> should remain empty. In contrast 13842to <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>, DNs of certificate authorities installed 13843in $<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> are not included in the client certificate 13844request message. MUAs with multiple client certificates may use the 13845list of preferred certificate authorities to select the correct 13846client certificate. You may want to put your "preferred" CA or 13847CAs in $<a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>, and install the remaining trusted CAs in 13848$<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a>. </p> 13849 13850<p> Example: </p> 13851 13852<pre> 13853<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> = /etc/postfix/certs 13854</pre> 13855 13856<p> This feature is available in Postfix 2.2 and later. </p> 13857 13858 13859</DD> 13860 13861<DT><b><a name="smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a> 13862(default: yes)</b></DT><DD> 13863 13864<p> Force the Postfix SMTP server to issue a TLS session id, even 13865when TLS session caching is turned off (<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a> 13866is empty). This behavior is compatible with Postfix < 2.3. </p> 13867 13868<p> With Postfix 2.3 and later the Postfix SMTP server can disable 13869session id generation when TLS session caching is turned off. This 13870keeps clients from caching sessions that almost certainly cannot 13871be re-used. </p> 13872 13873<p> By default, the Postfix SMTP server always generates TLS session 13874ids. This works around a known defect in mail client applications 13875such as MS Outlook, and may also prevent interoperability issues 13876with other MTAs. </p> 13877 13878<p> Example: </p> 13879 13880<pre> 13881<a href="postconf.5.html#smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a> = no 13882</pre> 13883 13884<p> This feature is available in Postfix 2.3 and later. </p> 13885 13886 13887</DD> 13888 13889<DT><b><a name="smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a> 13890(default: no)</b></DT><DD> 13891 13892<p> Ask a remote SMTP client for a client certificate. This 13893information is needed for certificate based mail relaying with, 13894for example, the <a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a> feature. </p> 13895 13896<p> Some clients such as Netscape will either complain if no 13897certificate is available (for the list of CAs in $<a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>) 13898or will offer multiple client certificates to choose from. This 13899may be annoying, so this option is "off" by default. </p> 13900 13901<p> This feature is available in Postfix 2.2 and later. </p> 13902 13903 13904</DD> 13905 13906<DT><b><a name="smtpd_tls_auth_only">smtpd_tls_auth_only</a> 13907(default: no)</b></DT><DD> 13908 13909<p> When TLS encryption is optional in the Postfix SMTP server, do 13910not announce or accept SASL authentication over unencrypted 13911connections. </p> 13912 13913<p> This feature is available in Postfix 2.2 and later. </p> 13914 13915 13916</DD> 13917 13918<DT><b><a name="smtpd_tls_ccert_verifydepth">smtpd_tls_ccert_verifydepth</a> 13919(default: 9)</b></DT><DD> 13920 13921<p> The verification depth for remote SMTP client certificates. A 13922depth of 1 is sufficient if the issuing CA is listed in a local CA 13923file. </p> 13924 13925<p> The default verification depth is 9 (the OpenSSL default) for 13926compatibility with earlier Postfix behavior. Prior to Postfix 2.5, 13927the default value was 5, but the limit was not actually enforced. If 13928you have set this to a lower non-default value, certificates with longer 13929trust chains may now fail to verify. Certificate chains with 1 or 2 13930CAs are common, deeper chains are more rare and any number between 5 13931and 9 should suffice in practice. You can choose a lower number if, 13932for example, you trust certificates directly signed by an issuing CA 13933but not any CAs it delegates to. </p> 13934 13935<p> This feature is available in Postfix 2.2 and later. </p> 13936 13937 13938</DD> 13939 13940<DT><b><a name="smtpd_tls_cert_file">smtpd_tls_cert_file</a> 13941(default: empty)</b></DT><DD> 13942 13943<p> File with the Postfix SMTP server RSA certificate in PEM format. 13944This file may also contain the Postfix SMTP server private RSA key. </p> 13945 13946<p> Public Internet MX hosts without certificates signed by a "reputable" 13947CA must generate, and be prepared to present to most clients, a 13948self-signed or private-CA signed certificate. The client will not be 13949able to authenticate the server, but unless it is running Postfix 2.3 or 13950similar software, it will still insist on a server certificate. </p> 13951 13952<p> For servers that are <b>not</b> public Internet MX hosts, Postfix 139532.3 supports configurations with no certificates. This entails the 13954use of just the anonymous TLS ciphers, which are not supported by 13955typical SMTP clients. Since such clients will not, as a rule, fall 13956back to plain text after a TLS handshake failure, the server will 13957be unable to receive email from TLS enabled clients. To avoid 13958accidental configurations with no certificates, Postfix 2.3 enables 13959certificate-less operation only when the administrator explicitly 13960sets "<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> = none". This ensures that new Postfix 13961configurations will not accidentally run with no certificates. </p> 13962 13963<p> Both RSA and DSA certificates are supported. When both types 13964are present, the cipher used determines which certificate will be 13965presented to the client. For Netscape and OpenSSL clients without 13966special cipher choices the RSA certificate is preferred. </p> 13967 13968<p> To enable a remote SMTP client to verify the Postfix SMTP server 13969certificate, the issuing CA certificates must be made available to the 13970client. You should include the required certificates in the server 13971certificate file, the server certificate first, then the issuing 13972CA(s) (bottom-up order). </p> 13973 13974<p> Example: the certificate for "server.example.com" was issued by 13975"intermediate CA" which itself has a certificate of "root CA". 13976Create the server.pem file with "cat server_cert.pem intermediate_CA.pem 13977root_CA.pem > server.pem". </p> 13978 13979<p> If you also want to verify client certificates issued by these 13980CAs, you can add the CA certificates to the <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>, in which 13981case it is not necessary to have them in the <a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> or 13982<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>. </p> 13983 13984<p> A certificate supplied here must be usable as an SSL server certificate 13985and hence pass the "openssl verify -purpose sslserver ..." test. </p> 13986 13987<p> Example: </p> 13988 13989<pre> 13990<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> = /etc/postfix/server.pem 13991</pre> 13992 13993<p> This feature is available in Postfix 2.2 and later. </p> 13994 13995 13996</DD> 13997 13998<DT><b><a name="smtpd_tls_cipherlist">smtpd_tls_cipherlist</a> 13999(default: empty)</b></DT><DD> 14000 14001<p> Obsolete Postfix < 2.3 control for the Postfix SMTP server TLS 14002cipher list. It is easy to create inter-operability problems by choosing 14003a non-default cipher list. Do not use a non-default TLS cipherlist for 14004MX hosts on the public Internet. Clients that begin the TLS handshake, 14005but are unable to agree on a common cipher, may not be able to send any 14006email to the SMTP server. Using a restricted cipher list may be more 14007appropriate for a dedicated MSA or an internal mailhub, where one can 14008exert some control over the TLS software and settings of the connecting 14009clients. </p> 14010 14011<p> <b>Note:</b> do not use "" quotes around the parameter value. </p> 14012 14013<p>This feature is available with Postfix version 2.2. It is not used with 14014Postfix 2.3 and later; use <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> instead. </p> 14015 14016 14017</DD> 14018 14019<DT><b><a name="smtpd_tls_ciphers">smtpd_tls_ciphers</a> 14020(default: export)</b></DT><DD> 14021 14022<p> The minimum TLS cipher grade that the Postfix SMTP server 14023will use with opportunistic TLS encryption. Cipher types listed in 14024<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> are excluded from the base definition of 14025the selected cipher grade. The default value "export" ensures maximum 14026inter-operability. Because encryption is optional, stronger controls 14027are not appropriate, and this setting SHOULD NOT be changed unless the 14028change is essential. </p> 14029 14030<p> When TLS is mandatory the cipher grade is chosen via the 14031<a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> configuration parameter, see there for syntax 14032details. </p> 14033 14034<p> Example: </p> 14035<pre> 14036<a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> = export 14037</pre> 14038 14039<p> This feature is available in Postfix 2.6 and later. With earlier Postfix 14040releases only the <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> parameter is implemented, 14041and opportunistic TLS always uses "export" or better (i.e. all) ciphers. </p> 14042 14043 14044</DD> 14045 14046<DT><b><a name="smtpd_tls_dcert_file">smtpd_tls_dcert_file</a> 14047(default: empty)</b></DT><DD> 14048 14049<p> File with the Postfix SMTP server DSA certificate in PEM format. 14050This file may also contain the Postfix SMTP server private DSA key. </p> 14051 14052<p> See the discussion under <a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> for more details. 14053</p> 14054 14055<p> Example: </p> 14056 14057<pre> 14058<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a> = /etc/postfix/server-dsa.pem 14059</pre> 14060 14061<p> This feature is available in Postfix 2.2 and later. </p> 14062 14063 14064</DD> 14065 14066<DT><b><a name="smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> 14067(default: empty)</b></DT><DD> 14068 14069<p> File with DH parameters that the Postfix SMTP server should 14070use with EDH ciphers. </p> 14071 14072<p> Instead of using the exact same parameter sets as distributed 14073with other TLS packages, it is more secure to generate your own 14074set of parameters with something like the following command: </p> 14075 14076<blockquote> 14077<pre> 14078openssl gendh -out /etc/postfix/dh_1024.pem -2 1024 14079</pre> 14080</blockquote> 14081 14082<p> Your actual source for entropy may differ. Some systems have 14083/dev/random; on other system you may consider using the "Entropy 14084Gathering Daemon EGD", available at <a href="http://egd.sourceforge.net/">http://egd.sourceforge.net/</a> 14085</p> 14086 14087<p> Example: </p> 14088 14089<pre> 14090<a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> = /etc/postfix/dh_1024.pem 14091</pre> 14092 14093<p>This feature is available with Postfix version 2.2.</p> 14094 14095 14096</DD> 14097 14098<DT><b><a name="smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a> 14099(default: empty)</b></DT><DD> 14100 14101<p> File with DH parameters that the Postfix SMTP server should 14102use with EDH ciphers. </p> 14103 14104<p> See also the discussion under the <a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> 14105configuration parameter. </p> 14106 14107<p> Example: </p> 14108 14109<pre> 14110<a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a> = /etc/postfix/dh_512.pem 14111</pre> 14112 14113<p>This feature is available with Postfix version 2.2.</p> 14114 14115 14116</DD> 14117 14118<DT><b><a name="smtpd_tls_dkey_file">smtpd_tls_dkey_file</a> 14119(default: $<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>)</b></DT><DD> 14120 14121<p> File with the Postfix SMTP server DSA private key in PEM format. 14122This file may be combined with the Postfix SMTP server DSA certificate 14123file specified with $<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>. </p> 14124 14125<p> The private key must be accessible without a pass-phrase, i.e. it 14126must not be encrypted. File permissions should grant read-only 14127access to the system superuser account ("root"), and no access 14128to anyone else. </p> 14129 14130<p> This feature is available in Postfix 2.2 and later. </p> 14131 14132 14133</DD> 14134 14135<DT><b><a name="smtpd_tls_eccert_file">smtpd_tls_eccert_file</a> 14136(default: empty)</b></DT><DD> 14137 14138<p> File with the Postfix SMTP server ECDSA certificate in PEM format. 14139This file may also contain the Postfix SMTP server private ECDSA key. </p> 14140 14141<p> See the discussion under <a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> for more details. </p> 14142 14143<p> Example: </p> 14144 14145<pre> 14146<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a> = /etc/postfix/ecdsa-scert.pem 14147</pre> 14148 14149<p> This feature is available in Postfix 2.6 and later, when Postfix is 14150compiled and linked with OpenSSL 1.0.0 or later. </p> 14151 14152 14153</DD> 14154 14155<DT><b><a name="smtpd_tls_eckey_file">smtpd_tls_eckey_file</a> 14156(default: $<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>)</b></DT><DD> 14157 14158<p> File with the Postfix SMTP server ECDSA private key in PEM format. 14159This file may be combined with the Postfix SMTP server ECDSA certificate 14160file specified with $<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>. </p> 14161 14162<p> The private key must be accessible without a pass-phrase, i.e. it 14163must not be encrypted. File permissions should grant read-only 14164access to the system superuser account ("root"), and no access 14165to anyone else. </p> 14166 14167<p> This feature is available in Postfix 2.6 and later, when Postfix is 14168compiled and linked with OpenSSL 1.0.0 or later. </p> 14169 14170 14171</DD> 14172 14173<DT><b><a name="smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> 14174(default: see "postconf -d" output)</b></DT><DD> 14175 14176<p> The Postfix SMTP server security grade for ephemeral elliptic-curve 14177Diffie-Hellman (EECDH) key exchange. </p> 14178 14179<p> The available choices are: </p> 14180 14181<dl> 14182 14183<dt><b>none</b></dt> <dd> Don't use EECDH. Ciphers based on EECDH key 14184exchange will be disabled. This is the default in Postfix versions 141852.6 and 2.7. </dd> 14186 14187<dt><b>strong</b></dt> <dd> Use EECDH with approximately 128 14188bits of security at a reasonable computational cost. This is the 14189current best-practice trade-off between security and computational 14190efficiency. This is the default in Postfix version 2.8 and later. 14191</dd> 14192 14193<dt><b>ultra</b></dt> <dd> Use EECDH with approximately 192 bits of 14194security at computational cost that is approximately twice as high 14195as 128 bit strength ECC. Barring significant progress in attacks on 14196elliptic curve crypto-systems, the "strong" curve is sufficient for most 14197users. </dd> 14198 14199</dl> 14200 14201<p> This feature is available in Postfix 2.6 and later, when it is 14202compiled and linked with OpenSSL 1.0.0 or later. </p> 14203 14204 14205</DD> 14206 14207<DT><b><a name="smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> 14208(default: empty)</b></DT><DD> 14209 14210<p> List of ciphers or cipher types to exclude from the SMTP server 14211cipher list at all TLS security levels. Excluding valid ciphers 14212can create interoperability problems. DO NOT exclude ciphers unless it 14213is essential to do so. This is not an OpenSSL cipherlist; it is a simple 14214list separated by whitespace and/or commas. The elements are a single 14215cipher, or one or more "+" separated cipher properties, in which case 14216only ciphers matching <b>all</b> the properties are excluded. </p> 14217 14218<p> Examples (some of these will cause problems): </p> 14219 14220<blockquote> 14221<pre> 14222<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = aNULL 14223<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = MD5, DES 14224<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = DES+MD5 14225<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = AES256-SHA, DES-CBC3-MD5 14226<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = kEDH+aRSA 14227</pre> 14228</blockquote> 14229 14230<p> The first setting disables anonymous ciphers. The next setting 14231disables ciphers that use the MD5 digest algorithm or the (single) DES 14232encryption algorithm. The next setting disables ciphers that use MD5 and 14233DES together. The next setting disables the two ciphers "AES256-SHA" 14234and "DES-CBC3-MD5". The last setting disables ciphers that use "EDH" 14235key exchange with RSA authentication. </p> 14236 14237<p> This feature is available in Postfix 2.3 and later. </p> 14238 14239 14240</DD> 14241 14242<DT><b><a name="smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> 14243(default: md5)</b></DT><DD> 14244 14245<p> The message digest algorithm used to construct client-certificate 14246fingerprints for <b><a href="postconf.5.html#check_ccert_access">check_ccert_access</a></b> and 14247<b><a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a></b>. The default algorithm is <b>md5</b>, 14248for backwards compatibility with Postfix releases prior to 2.5. 14249</p> 14250 14251<p> The best practice algorithm is now <b>sha1</b>. Recent advances in hash 14252function cryptanalysis have led to md5 being deprecated in favor of sha1. 14253However, as long as there are no known "second pre-image" attacks 14254against md5, its use in this context can still be considered safe. 14255</p> 14256 14257<p> While additional digest algorithms are often available with OpenSSL's 14258libcrypto, only those used by libssl in SSL cipher suites are available to 14259Postfix. For now this means just md5 or sha1. </p> 14260 14261<p> To find the fingerprint of a specific certificate file, with a 14262specific digest algorithm, run: </p> 14263 14264<blockquote> 14265<pre> 14266$ openssl x509 -noout -fingerprint -<i>digest</i> -in <i>certfile</i>.pem 14267</pre> 14268</blockquote> 14269 14270<p> The text to the right of "=" sign is the desired fingerprint. 14271For example: </p> 14272 14273<blockquote> 14274<pre> 14275$ openssl x509 -noout -fingerprint -sha1 -in cert.pem 14276SHA1 Fingerprint=D4:6A:AB:19:24:79:F8:32:BB:A6:CB:66:82:C0:8E:9B:EE:29:A8:1A 14277</pre> 14278</blockquote> 14279 14280<p> Example: client-certificate access table, with sha1 fingerprints: </p> 14281 14282<blockquote> 14283<pre> 14284/etc/postfix/<a href="postconf.5.html">main.cf</a>: 14285 <a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> = sha1 14286 <a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> = 14287 <a href="postconf.5.html#check_ccert_access">check_ccert_access</a> hash:/etc/postfix/access, 14288 reject 14289</pre> 14290<pre> 14291/etc/postfix/access: 14292 # Action folded to next line... 14293 AF:88:7C:AD:51:95:6F:36:96:F6:01:FB:2E:48:CD:AB:49:25:A2:3B 14294 OK 14295 85:16:78:FD:73:6E:CE:70:E0:31:5F:0D:3C:C8:6D:C4:2C:24:59:E1 14296 <a href="postconf.5.html#permit_auth_destination">permit_auth_destination</a> 14297</pre> 14298</blockquote> 14299 14300<p> This feature is available in Postfix 2.5 and later. </p> 14301 14302 14303</DD> 14304 14305<DT><b><a name="smtpd_tls_key_file">smtpd_tls_key_file</a> 14306(default: $<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a>)</b></DT><DD> 14307 14308<p> File with the Postfix SMTP server RSA private key in PEM format. 14309This file may be combined with the Postfix SMTP server RSA certificate 14310file specified with $<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a>. </p> 14311 14312<p> The private key must be accessible without a pass-phrase, i.e. it 14313must not be encrypted. File permissions should grant read-only 14314access to the system superuser account ("root"), and no access 14315to anyone else. </p> 14316 14317 14318</DD> 14319 14320<DT><b><a name="smtpd_tls_loglevel">smtpd_tls_loglevel</a> 14321(default: 0)</b></DT><DD> 14322 14323<p> Enable additional Postfix SMTP server logging of TLS activity. 14324Each logging level also includes the information that is logged at 14325a lower logging level. </p> 14326 14327<dl compact> 14328 14329<dt> </dt> <dd> 0 Disable logging of TLS activity. </dd> 14330 14331<dt> </dt> <dd> 1 Log TLS handshake and certificate information. </dd> 14332 14333<dt> </dt> <dd> 2 Log levels during TLS negotiation. </dd> 14334 14335<dt> </dt> <dd> 3 Log hexadecimal and ASCII dump of TLS negotiation 14336process. </dd> 14337 14338<dt> </dt> <dd> 4 Also log hexadecimal and ASCII dump of complete 14339transmission after STARTTLS. </dd> 14340 14341</dl> 14342 14343<p> Use "<a href="postconf.5.html#smtpd_tls_loglevel">smtpd_tls_loglevel</a> = 3" only in case of problems. Use of 14344loglevel 4 is strongly discouraged. </p> 14345 14346<p> This feature is available in Postfix 2.2 and later. </p> 14347 14348 14349</DD> 14350 14351<DT><b><a name="smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> 14352(default: medium)</b></DT><DD> 14353 14354<p> The minimum TLS cipher grade that the Postfix SMTP server will 14355use with mandatory TLS encryption. The default grade ("medium") is 14356sufficiently strong that any benefit from globally restricting TLS 14357sessions to a more stringent grade is likely negligible, especially 14358given the fact that many implementations still do not offer any stronger 14359("high" grade) ciphers, while those that do, will always use "high" 14360grade ciphers. So insisting on "high" grade ciphers is generally 14361counter-productive. Allowing "export" or "low" ciphers is typically 14362not a good idea, as systems limited to just these are limited to 14363obsolete browsers. No known SMTP clients fail to support at least 14364one "medium" or "high" grade cipher. </p> 14365 14366<p> The following cipher grades are supported: </p> 14367 14368<dl> 14369<dt><b>export</b></dt> 14370<dd> Enable "EXPORT" grade or stronger OpenSSL ciphers. 14371This is the most appropriate setting for public MX hosts, and is always 14372used with opportunistic TLS encryption. The underlying cipherlist 14373is specified via the <a href="postconf.5.html#tls_export_cipherlist">tls_export_cipherlist</a> configuration parameter, 14374which you are strongly encouraged to not change. </dd> 14375 14376<dt><b>low</b></dt> 14377<dd> Enable "LOW" grade or stronger OpenSSL ciphers. The 14378underlying cipherlist is specified via the <a href="postconf.5.html#tls_low_cipherlist">tls_low_cipherlist</a> 14379configuration parameter, which you are strongly encouraged to 14380not change. </dd> 14381 14382<dt><b>medium</b></dt> 14383<dd> Enable "MEDIUM" grade or stronger OpenSSL ciphers. These use 128-bit 14384or longer symmetric bulk-encryption keys. This is the default minimum 14385strength for mandatory TLS encryption. The underlying cipherlist is 14386specified via the <a href="postconf.5.html#tls_medium_cipherlist">tls_medium_cipherlist</a> configuration parameter, which 14387you are strongly encouraged to not change. </dd> 14388 14389<dt><b>high</b></dt> 14390<dd> Enable only "HIGH" grade OpenSSL ciphers. The 14391underlying cipherlist is specified via the <a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a> 14392configuration parameter, which you are strongly encouraged to 14393not change. </dd> 14394 14395<dt><b>null</b></dt> 14396<dd> Enable only the "NULL" OpenSSL ciphers, these provide authentication 14397without encryption. This setting is only appropriate in the rare 14398case that all clients are prepared to use NULL ciphers (not normally 14399enabled in TLS clients). The underlying cipherlist is specified via the 14400<a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> configuration parameter, which you are strongly 14401encouraged to not change. </dd> 14402 14403</dl> 14404 14405<p> Cipher types listed in 14406<a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> or <a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> are 14407excluded from the base definition of the selected cipher grade. See 14408<a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> for cipher controls that apply to opportunistic 14409TLS. </p> 14410 14411<p> The underlying cipherlists for grades other than "null" include 14412anonymous ciphers, but these are automatically filtered out if the 14413server is configured to ask for client certificates. You are very 14414unlikely to need to take any steps to exclude anonymous ciphers, they 14415are excluded automatically as required. If you must exclude anonymous 14416ciphers even when Postfix does not need or use peer certificates, set 14417"<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> = aNULL". To exclude anonymous ciphers only 14418when TLS is enforced, set "<a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> = aNULL". </p> 14419 14420<p> This feature is available in Postfix 2.3 and later. </p> 14421 14422 14423</DD> 14424 14425<DT><b><a name="smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> 14426(default: empty)</b></DT><DD> 14427 14428<p> Additional list of ciphers or cipher types to exclude from the 14429SMTP server cipher list at mandatory TLS security levels. This list 14430works in addition to the exclusions listed with <a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> 14431(see there for syntax details). </p> 14432 14433<p> This feature is available in Postfix 2.3 and later. </p> 14434 14435 14436</DD> 14437 14438<DT><b><a name="smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> 14439(default: SSLv3, TLSv1)</b></DT><DD> 14440 14441<p> The SSL/TLS protocols accepted by the Postfix SMTP server with 14442mandatory TLS encryption. If the list is empty, the server supports all 14443available SSL/TLS protocol versions. A non-empty value is a list 14444of protocol 14445names separated by whitespace, commas or colons. The supported protocol 14446names are "SSLv2", "SSLv3" and "TLSv1", and are not case sensitive. </p> 14447 14448<p> With Postfix ≥ 2.5 the parameter syntax is expanded to support 14449protocol exclusions. One can now explicitly exclude SSLv2 by setting 14450"<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2". To exclude both SSLv2 and 14451SSLv3 set "<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3". Listing 14452the protocols to include, rather than protocols to exclude, is still 14453supported, use the form you find more intuitive. </p> 14454 14455<p> Since SSL version 2 has known protocol weaknesses and is now 14456deprecated, the default setting excludes "SSLv2". This means that 14457by default, SSL version 2 will not be used at the "encrypt" security 14458level. </p> 14459 14460<p> Example: </p> 14461 14462<pre> 14463<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = TLSv1 14464# Alternative form with Postfix ≥ 2.5: 14465<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 14466</pre> 14467 14468<p> This feature is available in Postfix 2.3 and later. </p> 14469 14470 14471</DD> 14472 14473<DT><b><a name="smtpd_tls_protocols">smtpd_tls_protocols</a> 14474(default: empty)</b></DT><DD> 14475 14476<p> List of TLS protocols that the Postfix SMTP server will exclude 14477or include with opportunistic TLS encryption. This parameter SHOULD be 14478left at its default empty value, allowing all protocols to be used with 14479opportunistic TLS. </p> 14480 14481<p> In <a href="postconf.5.html">main.cf</a> the values are separated by whitespace, commas or 14482colons. An empty value means allow all protocols. The valid protocol 14483names, (see <b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" and 14484"TLSv1". In <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> table entries, "protocols" attribute 14485values are separated by a colon. </p> 14486 14487<p> To include a protocol list its name, to exclude it, prefix the name 14488with a "!" character. To exclude SSLv2 even for opportunistic TLS set 14489"<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2". To exclude both "SSLv2" and "SSLv3" set 14490"<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2, !SSLv3". Explicitly listing the protocols to 14491include, is supported, but not recommended. OpenSSL provides no mechanisms 14492for excluding protocols not known at compile-time. If Postfix is linked 14493against an OpenSSL library that supports additional protocol versions, 14494they cannot be excluded using either syntax. </p> 14495 14496<p> Example: </p> 14497<pre> 14498<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2 14499</pre> 14500 14501<p> This feature is available in Postfix 2.6 and later. </p> 14502 14503 14504</DD> 14505 14506<DT><b><a name="smtpd_tls_received_header">smtpd_tls_received_header</a> 14507(default: no)</b></DT><DD> 14508 14509<p> Request that the Postfix SMTP server produces Received: message 14510headers that include information about the protocol and cipher used, 14511as well as the client CommonName and client certificate issuer 14512CommonName. This is disabled by default, as the information may 14513be modified in transit through other mail servers. Only information 14514that was recorded by the final destination can be trusted. </p> 14515 14516<p> This feature is available in Postfix 2.2 and later. </p> 14517 14518 14519</DD> 14520 14521<DT><b><a name="smtpd_tls_req_ccert">smtpd_tls_req_ccert</a> 14522(default: no)</b></DT><DD> 14523 14524<p> With mandatory TLS encryption, require a trusted remote SMTP client 14525certificate in order to allow TLS connections to proceed. This 14526option implies "<a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a> = yes". </p> 14527 14528<p> When TLS encryption is optional, this setting is ignored with 14529a warning written to the mail log. </p> 14530 14531<p> This feature is available in Postfix 2.2 and later. </p> 14532 14533 14534</DD> 14535 14536<DT><b><a name="smtpd_tls_security_level">smtpd_tls_security_level</a> 14537(default: empty)</b></DT><DD> 14538 14539<p> The SMTP TLS security level for the Postfix SMTP server; when 14540a non-empty value is specified, this overrides the obsolete parameters 14541<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> and <a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>. This parameter is ignored with 14542"<a href="postconf.5.html#smtpd_tls_wrappermode">smtpd_tls_wrappermode</a> = yes". </p> 14543 14544<p> Specify one of the following security levels: </p> 14545 14546<dl> 14547 14548<dt><b>none</b></dt> <dd> TLS will not be used. </dd> 14549 14550<dt><b>may</b></dt> <dd> Opportunistic TLS: announce STARTTLS support 14551to SMTP clients, but do not require that clients use TLS encryption. 14552</dd> 14553 14554<dt><b>encrypt</b></dt> <dd>Mandatory TLS encryption: announce 14555STARTTLS support to SMTP clients, and require that clients use TLS 14556encryption. According to <a href="http://tools.ietf.org/html/rfc2487">RFC 2487</a> this MUST NOT be applied in case 14557of a publicly-referenced SMTP server. Instead, this option should 14558be used only on dedicated servers. </dd> 14559 14560</dl> 14561 14562<p> Note 1: the "fingerprint", "verify" and "secure" levels are not 14563supported here. 14564The Postfix SMTP server logs a warning and uses "encrypt" instead. 14565To verify SMTP client certificates, see <a href="TLS_README.html">TLS_README</a> for a discussion 14566of the <a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>, <a href="postconf.5.html#smtpd_tls_req_ccert">smtpd_tls_req_ccert</a>, and <a href="postconf.5.html#permit_tls_clientcerts">permit_tls_clientcerts</a> 14567features. </p> 14568 14569<p> Note 2: The parameter setting "<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> = 14570encrypt" implies "<a href="postconf.5.html#smtpd_tls_auth_only">smtpd_tls_auth_only</a> = yes".</p> 14571 14572<p> Note 3: when invoked via "sendmail -bs", Postfix will never 14573offer STARTTLS due to insufficient privileges to access the server 14574private key. This is intended behavior.</p> 14575 14576<p> This feature is available in Postfix 2.3 and later. </p> 14577 14578 14579</DD> 14580 14581<DT><b><a name="smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a> 14582(default: empty)</b></DT><DD> 14583 14584<p> Name of the file containing the optional Postfix SMTP server 14585TLS session cache. Specify a database type that supports enumeration, 14586such as <b>btree</b> or <b>sdbm</b>; there is no need to support 14587concurrent access. The file is created if it does not exist. The <a href="smtpd.8.html">smtpd(8)</a> 14588daemon does not use this parameter directly, rather the cache is 14589implemented indirectly in the <a href="tlsmgr.8.html">tlsmgr(8)</a> daemon. This means that 14590per-smtpd-instance <a href="master.5.html">master.cf</a> overrides of this parameter are not 14591effective. Note, that each of the cache databases supported by <a href="tlsmgr.8.html">tlsmgr(8)</a> 14592daemon: $<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a>, $<a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> 14593(and with Postfix 2.3 and later $<a href="postconf.5.html#lmtp_tls_session_cache_database">lmtp_tls_session_cache_database</a>), needs to be 14594stored separately. It is not at this time possible to store multiple 14595caches in a single database. </p> 14596 14597<p> Note: <b>dbm</b> databases are not suitable. TLS 14598session objects are too large. </p> 14599 14600<p> As of version 2.5, Postfix no longer uses root privileges when 14601opening this file. The file should now be stored under the Postfix-owned 14602<a href="postconf.5.html#data_directory">data_directory</a>. As a migration aid, an attempt to open the file 14603under a non-Postfix directory is redirected to the Postfix-owned 14604<a href="postconf.5.html#data_directory">data_directory</a>, and a warning is logged. </p> 14605 14606<p> Example: </p> 14607 14608<pre> 14609<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a> = btree:/var/db/postfix/smtpd_scache 14610</pre> 14611 14612<p> This feature is available in Postfix 2.2 and later. </p> 14613 14614 14615</DD> 14616 14617<DT><b><a name="smtpd_tls_session_cache_timeout">smtpd_tls_session_cache_timeout</a> 14618(default: 3600s)</b></DT><DD> 14619 14620<p> The expiration time of Postfix SMTP server TLS session cache 14621information. A cache cleanup is performed periodically 14622every $<a href="postconf.5.html#smtpd_tls_session_cache_timeout">smtpd_tls_session_cache_timeout</a> seconds. As with 14623$<a href="postconf.5.html#smtpd_tls_session_cache_database">smtpd_tls_session_cache_database</a>, this parameter is implemented in the 14624<a href="tlsmgr.8.html">tlsmgr(8)</a> daemon and therefore per-smtpd-instance <a href="master.5.html">master.cf</a> overrides 14625are not possible. </p> 14626 14627<p> This feature is available in Postfix 2.2 and later. </p> 14628 14629 14630</DD> 14631 14632<DT><b><a name="smtpd_tls_wrappermode">smtpd_tls_wrappermode</a> 14633(default: no)</b></DT><DD> 14634 14635<p> Run the Postfix SMTP server in the non-standard "wrapper" mode, 14636instead of using the STARTTLS command. </p> 14637 14638<p> If you want to support this service, enable a special port in 14639<a href="master.5.html">master.cf</a>, and specify "-o <a href="postconf.5.html#smtpd_tls_wrappermode">smtpd_tls_wrappermode</a>=yes" on the SMTP 14640server's command line. Port 465 (smtps) was once chosen for this 14641purpose. </p> 14642 14643<p> This feature is available in Postfix 2.2 and later. </p> 14644 14645 14646</DD> 14647 14648<DT><b><a name="smtpd_use_tls">smtpd_use_tls</a> 14649(default: no)</b></DT><DD> 14650 14651<p> Opportunistic TLS: announce STARTTLS support to SMTP clients, 14652but do not require that clients use TLS encryption. </p> 14653 14654<p> Note: when invoked via "<b>sendmail -bs</b>", Postfix will never offer 14655STARTTLS due to insufficient privileges to access the server private 14656key. This is intended behavior. </p> 14657 14658<p> This feature is available in Postfix 2.2 and later. With 14659Postfix 2.3 and later use <a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> instead. </p> 14660 14661 14662</DD> 14663 14664<DT><b><a name="soft_bounce">soft_bounce</a> 14665(default: no)</b></DT><DD> 14666 14667<p> 14668Safety net to keep mail queued that would otherwise be returned to 14669the sender. This parameter disables locally-generated bounces, 14670and prevents the Postfix SMTP server from rejecting mail permanently, 14671by changing 5xx reply codes into 4xx. However, <a href="postconf.5.html#soft_bounce">soft_bounce</a> is no 14672cure for address rewriting mistakes or mail routing mistakes. 14673</p> 14674 14675<p> 14676Example: 14677</p> 14678 14679<pre> 14680<a href="postconf.5.html#soft_bounce">soft_bounce</a> = yes 14681</pre> 14682 14683 14684</DD> 14685 14686<DT><b><a name="stale_lock_time">stale_lock_time</a> 14687(default: 500s)</b></DT><DD> 14688 14689<p> 14690The time after which a stale exclusive mailbox lockfile is removed. 14691This is used for delivery to file or mailbox. 14692</p> 14693 14694<p> 14695Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 14696The default time unit is s (seconds). 14697</p> 14698 14699 14700</DD> 14701 14702<DT><b><a name="stress">stress</a> 14703(default: empty)</b></DT><DD> 14704 14705<p> This feature is documented in the <a href="STRESS_README.html">STRESS_README</a> document. </p> 14706 14707<p> This feature is available in Postfix 2.5 and later. </p> 14708 14709 14710</DD> 14711 14712<DT><b><a name="strict_7bit_headers">strict_7bit_headers</a> 14713(default: no)</b></DT><DD> 14714 14715<p> 14716Reject mail with 8-bit text in message headers. This blocks mail 14717from poorly written applications. 14718</p> 14719 14720<p> 14721This feature should not be enabled on a general purpose mail server, 14722because it is likely to reject legitimate email. 14723</p> 14724 14725<p> 14726This feature is available in Postfix 2.0 and later. 14727</p> 14728 14729 14730</DD> 14731 14732<DT><b><a name="strict_8bitmime">strict_8bitmime</a> 14733(default: no)</b></DT><DD> 14734 14735<p> 14736Enable both <a href="postconf.5.html#strict_7bit_headers">strict_7bit_headers</a> and <a href="postconf.5.html#strict_8bitmime_body">strict_8bitmime_body</a>. 14737</p> 14738 14739<p> 14740This feature should not be enabled on a general purpose mail server, 14741because it is likely to reject legitimate email. 14742</p> 14743 14744<p> 14745This feature is available in Postfix 2.0 and later. 14746</p> 14747 14748 14749</DD> 14750 14751<DT><b><a name="strict_8bitmime_body">strict_8bitmime_body</a> 14752(default: no)</b></DT><DD> 14753 14754<p> 14755Reject 8-bit message body text without 8-bit MIME content encoding 14756information. This blocks mail from poorly written applications. 14757</p> 14758 14759<p> 14760Unfortunately, this also rejects majordomo approval requests when 14761the included request contains valid 8-bit MIME mail, and it rejects 14762bounces from mailers that do not MIME encapsulate 8-bit content 14763(for example, bounces from qmail or from old versions of Postfix). 14764</p> 14765 14766<p> 14767This feature should not be enabled on a general purpose mail server, 14768because it is likely to reject legitimate email. 14769</p> 14770 14771<p> 14772This feature is available in Postfix 2.0 and later. 14773</p> 14774 14775 14776</DD> 14777 14778<DT><b><a name="strict_mailbox_ownership">strict_mailbox_ownership</a> 14779(default: yes)</b></DT><DD> 14780 14781<p> Defer delivery when a mailbox file is not owned by its recipient. 14782The default setting is not backwards compatible. </p> 14783 14784<p> This feature is available in Postfix 2.5.3 and later. </p> 14785 14786 14787</DD> 14788 14789<DT><b><a name="strict_mime_encoding_domain">strict_mime_encoding_domain</a> 14790(default: no)</b></DT><DD> 14791 14792<p> 14793Reject mail with invalid Content-Transfer-Encoding: information 14794for the message/* or multipart/* MIME content types. This blocks 14795mail from poorly written software. 14796</p> 14797 14798<p> 14799This feature should not be enabled on a general purpose mail server, 14800because it will reject mail after a single violation. 14801</p> 14802 14803<p> 14804This feature is available in Postfix 2.0 and later. 14805</p> 14806 14807 14808</DD> 14809 14810<DT><b><a name="strict_rfc821_envelopes">strict_rfc821_envelopes</a> 14811(default: no)</b></DT><DD> 14812 14813<p> 14814Require that addresses received in SMTP MAIL FROM and RCPT TO 14815commands are enclosed with <>, and that those addresses do 14816not contain <a href="http://tools.ietf.org/html/rfc822">RFC 822</a> style comments or phrases. This stops mail 14817from poorly written software. 14818</p> 14819 14820<p> 14821By default, the Postfix SMTP server accepts <a href="http://tools.ietf.org/html/rfc822">RFC 822</a> syntax in MAIL 14822FROM and RCPT TO addresses. 14823</p> 14824 14825 14826</DD> 14827 14828<DT><b><a name="sun_mailtool_compatibility">sun_mailtool_compatibility</a> 14829(default: no)</b></DT><DD> 14830 14831<p> 14832Obsolete SUN mailtool compatibility feature. Instead, use 14833"<a href="postconf.5.html#mailbox_delivery_lock">mailbox_delivery_lock</a> = dotlock". 14834</p> 14835 14836 14837</DD> 14838 14839<DT><b><a name="swap_bangpath">swap_bangpath</a> 14840(default: yes)</b></DT><DD> 14841 14842<p> 14843Enable the rewriting of "site!user" into "user@site". This is 14844necessary if your machine is connected to UUCP networks. It is 14845enabled by default. 14846</p> 14847 14848<p> Note: with Postfix version 2.2, message header address rewriting 14849happens only when one of the following conditions is true: </p> 14850 14851<ul> 14852 14853<li> The message is received with the Postfix <a href="sendmail.1.html">sendmail(1)</a> command, 14854 14855<li> The message is received from a network client that matches 14856$<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a>, 14857 14858<li> The message is received from the network, and the 14859<a href="postconf.5.html#remote_header_rewrite_domain">remote_header_rewrite_domain</a> parameter specifies a non-empty value. 14860 14861</ul> 14862 14863<p> To get the behavior before Postfix version 2.2, specify 14864"<a href="postconf.5.html#local_header_rewrite_clients">local_header_rewrite_clients</a> = static:all". </p> 14865 14866<p> 14867Example: 14868</p> 14869 14870<pre> 14871<a href="postconf.5.html#swap_bangpath">swap_bangpath</a> = no 14872</pre> 14873 14874 14875</DD> 14876 14877<DT><b><a name="syslog_facility">syslog_facility</a> 14878(default: mail)</b></DT><DD> 14879 14880<p> 14881The syslog facility of Postfix logging. Specify a facility as 14882defined in syslog.conf(5). The default facility is "mail". 14883</p> 14884 14885<p> 14886Warning: a non-default <a href="postconf.5.html#syslog_facility">syslog_facility</a> setting takes effect only 14887after a Postfix process has completed initialization. Errors during 14888process initialization will be logged with the default facility. 14889Examples are errors while parsing the command line arguments, and 14890errors while accessing the Postfix <a href="postconf.5.html">main.cf</a> configuration file. 14891</p> 14892 14893 14894</DD> 14895 14896<DT><b><a name="syslog_name">syslog_name</a> 14897(default: see "postconf -d" output)</b></DT><DD> 14898 14899<p> 14900The mail system name that is prepended to the process name in syslog 14901records, so that "smtpd" becomes, for example, "postfix/smtpd". 14902</p> 14903 14904<p> 14905Warning: a non-default <a href="postconf.5.html#syslog_name">syslog_name</a> setting takes effect only after 14906a Postfix process has completed initialization. Errors during 14907process initialization will be logged with the default name. Examples 14908are errors while parsing the command line arguments, and errors 14909while accessing the Postfix <a href="postconf.5.html">main.cf</a> configuration file. 14910</p> 14911 14912 14913</DD> 14914 14915<DT><b><a name="tcp_windowsize">tcp_windowsize</a> 14916(default: 0)</b></DT><DD> 14917 14918<p> An optional workaround for routers that break TCP window scaling. 14919Specify a value > 0 and < 65536 to enable this feature. With 14920Postfix TCP servers (<a href="smtpd.8.html">smtpd(8)</a>, <a href="qmqpd.8.html">qmqpd(8)</a>), this feature is implemented 14921by the Postfix <a href="master.8.html">master(8)</a> daemon. </p> 14922 14923<p> To change this parameter without stopping Postfix, you need to 14924first terminate all Postfix TCP servers: </p> 14925 14926<blockquote> 14927<pre> 14928# postconf -e <a href="postconf.5.html#master_service_disable">master_service_disable</a>=inet 14929# postfix reload 14930</pre> 14931</blockquote> 14932 14933<p> This immediately terminates all processes that accept network 14934connections. Next, you enable Postfix TCP servers with the updated 14935<a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a> setting: </p> 14936 14937<blockquote> 14938<pre> 14939# postconf -e <a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a>=65535 <a href="postconf.5.html#master_service_disable">master_service_disable</a>= 14940# postfix reload 14941</pre> 14942</blockquote> 14943 14944<p> If you skip these steps with a running Postfix system, then the 14945<a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a> change will work only for Postfix TCP clients (<a href="smtp.8.html">smtp(8)</a>, 14946<a href="lmtp.8.html">lmtp(8)</a>). </p> 14947 14948<p> This feature is available in Postfix 2.6 and later. </p> 14949 14950 14951</DD> 14952 14953<DT><b><a name="tls_append_default_CA">tls_append_default_CA</a> 14954(default: no)</b></DT><DD> 14955 14956<p> Append the system-supplied default certificate authority 14957certificates to the ones specified with *_tls_CApath or *_tls_CAfile. 14958The default is "no"; this prevents Postfix from trusting third-party 14959certificates and giving them relay permission with 14960<a href="postconf.5.html#permit_tls_all_clientcerts">permit_tls_all_clientcerts</a>. </p> 14961 14962<p> This feature is available in Postfix 2.4.15, 2.5.11, 2.6.8, 149632.7.2 and later versions. Specify "<a href="postconf.5.html#tls_append_default_CA">tls_append_default_CA</a> = yes" for 14964backwards compatibility, to avoid breaking certificate verification 14965with sites that don't use <a href="postconf.5.html#permit_tls_all_clientcerts">permit_tls_all_clientcerts</a>. </p> 14966 14967 14968</DD> 14969 14970<DT><b><a name="tls_daemon_random_bytes">tls_daemon_random_bytes</a> 14971(default: 32)</b></DT><DD> 14972 14973<p> The number of pseudo-random bytes that an <a href="smtp.8.html">smtp(8)</a> or <a href="smtpd.8.html">smtpd(8)</a> 14974process requests from the <a href="tlsmgr.8.html">tlsmgr(8)</a> server in order to seed its 14975internal pseudo random number generator (PRNG). The default of 32 14976bytes (equivalent to 256 bits) is sufficient to generate a 128bit 14977(or 168bit) session key. </p> 14978 14979<p> This feature is available in Postfix 2.2 and later. </p> 14980 14981 14982</DD> 14983 14984<DT><b><a name="tls_disable_workarounds">tls_disable_workarounds</a> 14985(default: see "postconf -d" output)</b></DT><DD> 14986 14987<p> List or bit-mask of OpenSSL bug work-arounds to disable. </p> 14988 14989<p> The OpenSSL toolkit includes a set of work-arounds for buggy SSL/TLS 14990implementations. Applications, such as Postfix, that want to maximize 14991interoperability ask the OpenSSL library to enable the full set of 14992recommended work-arounds. </p> 14993 14994<p> From time to time, it is discovered that a work-around creates a 14995security issue, and should no longer be used. If upgrading OpenSSL 14996to a fixed version is not an option or an upgrade is not available 14997in a timely manner, or in closed environments where no buggy clients 14998or servers exist, it may be appropriate to disable some or all of the 14999OpenSSL interoperability work-arounds. This parameter specifies which 15000bug work-arounds to disable. </p> 15001 15002<p> If the value of the parameter is a hexadecimal long integer starting 15003with "0x", the bug work-arounds corresponding to the bits specified in 15004its value are removed from the <b>SSL_OP_ALL</b> work-around bit-mask 15005(see openssl/ssl.h and SSL_CTX_set_options(3)). You can specify more 15006bits than are present in SSL_OP_ALL, excess bits are ignored. Specifying 150070xFFFFFFFF disables all bug-workarounds on a 32-bit system. This should 15008also be sufficient on 64-bit systems, until OpenSSL abandons support 15009for 32-bit systems and starts using the high 32 bits of a 64-bit 15010bug-workaround mask. </p> 15011 15012<p> Otherwise, the parameter is a white-space or comma separated list 15013of specific named bug work-arounds chosen from the list below. It 15014is possible that your OpenSSL version includes new bug work-arounds 15015added after your Postfix source code was last updated, in that case 15016you can only disable one of these via the hexadecimal syntax above. </p> 15017 15018<dl> 15019 15020<dt><b>MICROSOFT_SESS_ID_BUG</b></dt> <dd>See SSL_CTX_set_options(3)</dd> 15021 15022<dt><b>NETSCAPE_CHALLENGE_BUG</b></dt> <dd>See SSL_CTX_set_options(3)</dd> 15023 15024<dt><b>LEGACY_SERVER_CONNECT</b></dt> <dd>See SSL_CTX_set_options(3)</dd> 15025 15026<dt><b>NETSCAPE_REUSE_CIPHER_CHANGE_BUG</b></dt> <dd> also aliased 15027as <b>CVE-2010-4180</b>. Postfix 2.8 disables this work-around by 15028default with OpenSSL versions that may predate the fix. Fixed in 15029OpenSSL 0.9.8q and OpenSSL 1.0.0c.</dd> 15030 15031<dt><b>SSLREF2_REUSE_CERT_TYPE_BUG</b></dt> <dd>See 15032SSL_CTX_set_options(3)</dd> 15033 15034<dt><b>MICROSOFT_BIG_SSLV3_BUFFER</b></dt> <dd>See 15035SSL_CTX_set_options(3)</dd> 15036 15037<dt><b>MSIE_SSLV2_RSA_PADDING</b></dt> <dd> also aliased as 15038<b>CVE-2005-2969</b>. Postfix 2.8 disables this work-around by 15039default with OpenSSL versions that may predate the fix. Fixed in 15040OpenSSL 0.9.7h and OpenSSL 0.9.8a.</dd> 15041 15042<dt><b>SSLEAY_080_CLIENT_DH_BUG</b></dt> <dd>See 15043SSL_CTX_set_options(3)</dd> 15044 15045<dt><b>TLS_D5_BUG</b></dt> <dd>See SSL_CTX_set_options(3)</dd> 15046 15047<dt><b>TLS_BLOCK_PADDING_BUG</b></dt> <dd>See SSL_CTX_set_options(3)</dd> 15048 15049<dt><b>TLS_ROLLBACK_BUG</b></dt> <dd>See SSL_CTX_set_options(3). 15050This is disabled in OpenSSL 0.9.7 and later. Nobody should still 15051be using 0.9.6! </dd> 15052 15053<dt><b>DONT_INSERT_EMPTY_FRAGMENTS</b></dt> <dd>See 15054SSL_CTX_set_options(3)</dd> 15055 15056<dt><b>CRYPTOPRO_TLSEXT_BUG</b></dt> <dd>New with GOST support in 15057OpenSSL 1.0.0.</dd> 15058 15059</dl> 15060 15061<p> This feature is available in Postfix 2.8 and later. </p> 15062 15063 15064</DD> 15065 15066<DT><b><a name="tls_eecdh_strong_curve">tls_eecdh_strong_curve</a> 15067(default: prime256v1)</b></DT><DD> 15068 15069<p> The elliptic curve used by the SMTP server for sensibly strong 15070ephemeral ECDH key exchange. This curve is used by the Postfix SMTP 15071server when "<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> = strong". The phrase "sensibly 15072strong" means approximately 128-bit security based on best known 15073attacks. The selected curve must be implemented by OpenSSL (as 15074reported by ecparam(1) with the "-list_curves" option) and be one 15075of the curves listed in Section 5.1.1 of <a href="http://tools.ietf.org/html/rfc4492">RFC 4492</a>. You should not 15076generally change this setting. </p> 15077 15078<p> This default curve is specified in NSA "Suite B" Cryptography 15079(see <a href="http://www.nsa.gov/ia/industry/crypto_suite_b.cfm">http://www.nsa.gov/ia/industry/crypto_suite_b.cfm</a>) for 15080information classified as SECRET. </p> 15081 15082<p> Note: elliptic curve names are poorly standardized; different 15083standards groups are assigning different names to the same underlying 15084curves. The curve with the X9.62 name "prime256v1" is also known 15085under the SECG name "secp256r1", but OpenSSL does not recognize the 15086latter name. </p> 15087 15088<p> This feature is available in Postfix 2.6 and later, when it is 15089compiled and linked with OpenSSL 1.0.0 or later. </p> 15090 15091 15092</DD> 15093 15094<DT><b><a name="tls_eecdh_ultra_curve">tls_eecdh_ultra_curve</a> 15095(default: secp384r1)</b></DT><DD> 15096 15097<p> The elliptic curve used by the SMTP server for maximally strong 15098ephemeral ECDH key exchange. This curve is used by the Postfix SMTP 15099server when "<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> = ultra". The phrase "maximally 15100strong" means approximately 192-bit security based on best known attacks. 15101This additional strength comes at a significant computational cost, most 15102users should instead set "<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> = strong". The selected 15103curve must be implemented by OpenSSL (as reported by ecparam(1) with the 15104"-list_curves" option) and be one of the curves listed in Section 5.1.1 15105of <a href="http://tools.ietf.org/html/rfc4492">RFC 4492</a>. You should not generally change this setting. </p> 15106 15107<p> This default "ultra" curve is specified in NSA "Suite B" Cryptography 15108(see <a href="http://www.nsa.gov/ia/industry/crypto_suite_b.cfm">http://www.nsa.gov/ia/industry/crypto_suite_b.cfm</a>) for information 15109classified as TOP SECRET. </p> 15110 15111<p> This feature is available in Postfix 2.6 and later, when it is 15112compiled and linked with OpenSSL 1.0.0 or later. </p> 15113 15114 15115</DD> 15116 15117<DT><b><a name="tls_export_cipherlist">tls_export_cipherlist</a> 15118(default: ALL:+RC4:@STRENGTH)</b></DT><DD> 15119 15120<p> The OpenSSL cipherlist for "EXPORT" or higher grade ciphers. This 15121defines the meaning of the "export" setting in <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a>, 15122<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and <a href="postconf.5.html#lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a>. This is 15123the cipherlist for the opportunistic ("may") TLS client security 15124level and is the default cipherlist for the SMTP server. You are 15125strongly encouraged to not change this setting. With OpenSSL 1.0.0 and 15126later the cipherlist may start with an "aNULL:" prefix, which restores 15127the 0.9.8-compatible ordering of the aNULL ciphers to the top of the 15128list when they are enabled. This prefix is not needed with previous 15129OpenSSL releases. </p> 15130 15131<p> This feature is available in Postfix 2.3 and later. </p> 15132 15133 15134</DD> 15135 15136<DT><b><a name="tls_high_cipherlist">tls_high_cipherlist</a> 15137(default: ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)</b></DT><DD> 15138 15139<p> The OpenSSL cipherlist for "HIGH" grade ciphers. This defines 15140the meaning of the "high" setting in <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a>, 15141<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and <a href="postconf.5.html#lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a>. You are 15142strongly encouraged to not change this setting. With OpenSSL 1.0.0 and 15143later the cipherlist may start with an "aNULL:" prefix, which restores 15144the 0.9.8-compatible ordering of the aNULL ciphers to the top of the 15145list when they are enabled. This prefix is not needed with previous 15146OpenSSL releases. </p> 15147 15148<p> This feature is available in Postfix 2.3 and later. </p> 15149 15150 15151</DD> 15152 15153<DT><b><a name="tls_low_cipherlist">tls_low_cipherlist</a> 15154(default: ALL:!EXPORT:+RC4:@STRENGTH)</b></DT><DD> 15155 15156<p> The OpenSSL cipherlist for "LOW" or higher grade ciphers. This defines 15157the meaning of the "low" setting in <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a>, 15158<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and <a href="postconf.5.html#lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a>. You are 15159strongly encouraged to not change this setting. With OpenSSL 1.0.0 and 15160later the cipherlist may start with an "aNULL:" prefix, which restores 15161the 0.9.8-compatible ordering of the aNULL ciphers to the top of the 15162list when they are enabled. This prefix is not needed with previous 15163OpenSSL releases. </p> 15164 15165<p> This feature is available in Postfix 2.3 and later. </p> 15166 15167 15168</DD> 15169 15170<DT><b><a name="tls_medium_cipherlist">tls_medium_cipherlist</a> 15171(default: ALL:!EXPORT:!LOW:+RC4:@STRENGTH)</b></DT><DD> 15172 15173<p> The OpenSSL cipherlist for "MEDIUM" or higher grade ciphers. This 15174defines the meaning of the "medium" setting in <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a>, 15175<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and <a href="postconf.5.html#lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a>. This is 15176the default cipherlist for mandatory TLS encryption in the TLS 15177client (with anonymous ciphers disabled when verifying server 15178certificates). You are strongly encouraged to not change this 15179setting. With OpenSSL 1.0.0 and later the cipherlist may start with an 15180"aNULL:" prefix, which restores the 0.9.8-compatible ordering of the 15181aNULL ciphers to the top of the list when they are enabled. This prefix 15182is not needed with previous OpenSSL releases. </p> 15183 15184<p> This feature is available in Postfix 2.3 and later. </p> 15185 15186 15187</DD> 15188 15189<DT><b><a name="tls_null_cipherlist">tls_null_cipherlist</a> 15190(default: eNULL:!aNULL)</b></DT><DD> 15191 15192<p> The OpenSSL cipherlist for "NULL" grade ciphers that provide 15193authentication without encryption. This defines the meaning of the "null" 15194setting in smtpd_mandatory_tls_ciphers, <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> and 15195<a href="postconf.5.html#lmtp_tls_mandatory_ciphers">lmtp_tls_mandatory_ciphers</a>. You are strongly encouraged to not 15196change this setting. </p> 15197 15198<p> This feature is available in Postfix 2.3 and later. </p> 15199 15200 15201</DD> 15202 15203<DT><b><a name="tls_preempt_cipherlist">tls_preempt_cipherlist</a> 15204(default: no)</b></DT><DD> 15205 15206<p> With SSLv3 and later, use the server's cipher preference order 15207instead of the client's cipher preference order. </p> 15208 15209<p> By default, the OpenSSL server selects the client's most preferred 15210cipher that the server supports. With SSLv3 and later, the server may 15211choose its own most preferred cipher that is supported (offered) by 15212the client. Setting "<a href="postconf.5.html#tls_preempt_cipherlist">tls_preempt_cipherlist</a> = yes" enables server cipher 15213preferences. </p> 15214 15215<p> While server cipher selection may in some cases lead to a more secure 15216or performant cipher choice, there is some risk of interoperability 15217issues. In the past, some SSL clients have listed lower priority ciphers 15218that they did not implement correctly. If the server chooses a cipher 15219that the client prefers less, it may select a cipher whose client 15220implementation is flawed. </p> 15221 15222<p> This feature is available in Postfix 2.8 and later, in combination 15223with OpenSSL 0.9.7 and later. </p> 15224 15225 15226</DD> 15227 15228<DT><b><a name="tls_random_bytes">tls_random_bytes</a> 15229(default: 32)</b></DT><DD> 15230 15231<p> The number of bytes that <a href="tlsmgr.8.html">tlsmgr(8)</a> reads from $<a href="postconf.5.html#tls_random_source">tls_random_source</a> 15232when (re)seeding the in-memory pseudo random number generator (PRNG) 15233pool. The default of 32 bytes (256 bits) is good enough for 128bit 15234symmetric keys. If using EGD or a device file, a maximum of 255 15235bytes is read. </p> 15236 15237<p> This feature is available in Postfix 2.2 and later. </p> 15238 15239 15240</DD> 15241 15242<DT><b><a name="tls_random_exchange_name">tls_random_exchange_name</a> 15243(default: see "postconf -d" output)</b></DT><DD> 15244 15245<p> Name of the pseudo random number generator (PRNG) state file 15246that is maintained by <a href="tlsmgr.8.html">tlsmgr(8)</a>. The file is created when it does 15247not exist, and its length is fixed at 1024 bytes. </p> 15248 15249<p> As of version 2.5, Postfix no longer uses root privileges when 15250opening this file, and the default file location was changed from 15251${<a href="postconf.5.html#config_directory">config_directory</a>}/prng_exch to ${<a href="postconf.5.html#data_directory">data_directory</a>}/prng_exch. As 15252a migration aid, an attempt to open the file under a non-Postfix 15253directory is redirected to the Postfix-owned <a href="postconf.5.html#data_directory">data_directory</a>, and a 15254warning is logged. </p> 15255 15256<p> This feature is available in Postfix 2.2 and later. </p> 15257 15258 15259</DD> 15260 15261<DT><b><a name="tls_random_prng_update_period">tls_random_prng_update_period</a> 15262(default: 3600s)</b></DT><DD> 15263 15264<p> The time between attempts by <a href="tlsmgr.8.html">tlsmgr(8)</a> to save the state of 15265the pseudo random number generator (PRNG) to the file specified 15266with $<a href="postconf.5.html#tls_random_exchange_name">tls_random_exchange_name</a>. </p> 15267 15268<p> This feature is available in Postfix 2.2 and later. </p> 15269 15270 15271</DD> 15272 15273<DT><b><a name="tls_random_reseed_period">tls_random_reseed_period</a> 15274(default: 3600s)</b></DT><DD> 15275 15276<p> The maximal time between attempts by <a href="tlsmgr.8.html">tlsmgr(8)</a> to re-seed the 15277in-memory pseudo random number generator (PRNG) pool from external 15278sources. The actual time between re-seeding attempts is calculated 15279using the PRNG, and is between 0 and the time specified. </p> 15280 15281<p> This feature is available in Postfix 2.2 and later. </p> 15282 15283 15284</DD> 15285 15286<DT><b><a name="tls_random_source">tls_random_source</a> 15287(default: see "postconf -d" output)</b></DT><DD> 15288 15289<p> The external entropy source for the in-memory <a href="tlsmgr.8.html">tlsmgr(8)</a> pseudo 15290random number generator (PRNG) pool. Be sure to specify a non-blocking 15291source. If this source is not a regular file, the entropy source 15292type must be prepended: egd:/path/to/egd_socket for a source with 15293EGD compatible socket interface, or dev:/path/to/device for a 15294device file. </p> 15295 15296<p> Note: on OpenBSD systems specify /dev/arandom when /dev/urandom 15297gives timeout errors. </p> 15298 15299<p> This feature is available in Postfix 2.2 and later. </p> 15300 15301 15302</DD> 15303 15304<DT><b><a name="tlsproxy_enforce_tls">tlsproxy_enforce_tls</a> 15305(default: $<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b></DT><DD> 15306 15307<p> Mandatory TLS: announce STARTTLS support to SMTP clients, and 15308require that clients use TLS encryption. See <a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a> for 15309further details. </p> 15310 15311<p> This feature is available in Postfix 2.8 and later. </p> 15312 15313 15314</DD> 15315 15316<DT><b><a name="tlsproxy_service_name">tlsproxy_service_name</a> 15317(default: tlsproxy)</b></DT><DD> 15318 15319<p> The name of the <a href="tlsproxy.8.html">tlsproxy(8)</a> service entry in <a href="master.5.html">master.cf</a>. This 15320service performs plaintext <=> TLS ciphertext conversion. <p> 15321 15322<p> This feature is available in Postfix 2.8 and later. </p> 15323 15324 15325</DD> 15326 15327<DT><b><a name="tlsproxy_tls_CAfile">tlsproxy_tls_CAfile</a> 15328(default: $<a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>)</b></DT><DD> 15329 15330<p> A file containing (PEM format) CA certificates of root CAs 15331trusted to sign either remote SMTP client certificates or intermediate 15332CA certificates. See <a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a> for further details. </p> 15333 15334<p> This feature is available in Postfix 2.8 and later. </p> 15335 15336 15337</DD> 15338 15339<DT><b><a name="tlsproxy_tls_CApath">tlsproxy_tls_CApath</a> 15340(default: $<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a>)</b></DT><DD> 15341 15342<p> A directory containing (PEM format) CA certificates of root CAs 15343trusted to sign either remote SMTP client certificates or intermediate 15344CA certificates. See <a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a> for further details. </p> 15345 15346<p> This feature is available in Postfix 2.8 and later. </p> 15347 15348 15349</DD> 15350 15351<DT><b><a name="tlsproxy_tls_always_issue_session_ids">tlsproxy_tls_always_issue_session_ids</a> 15352(default: $<a href="postconf.5.html#smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a>)</b></DT><DD> 15353 15354<p> Force the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server to issue a TLS session id, 15355even when TLS session caching is turned off. See 15356<a href="postconf.5.html#smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a> for further details. </p> 15357 15358<p> This feature is available in Postfix 2.8 and later. </p> 15359 15360 15361</DD> 15362 15363<DT><b><a name="tlsproxy_tls_ask_ccert">tlsproxy_tls_ask_ccert</a> 15364(default: $<a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>)</b></DT><DD> 15365 15366<p> Ask a remote SMTP client for a client certificate. See 15367<a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a> for further details. </p> 15368 15369<p> This feature is available in Postfix 2.8 and later. </p> 15370 15371 15372</DD> 15373 15374<DT><b><a name="tlsproxy_tls_ccert_verifydepth">tlsproxy_tls_ccert_verifydepth</a> 15375(default: $<a href="postconf.5.html#smtpd_tls_ccert_verifydepth">smtpd_tls_ccert_verifydepth</a>)</b></DT><DD> 15376 15377<p> The verification depth for remote SMTP client certificates. A 15378depth of 1 is sufficient if the issuing CA is listed in a local CA 15379file. See <a href="postconf.5.html#smtpd_tls_ccert_verifydepth">smtpd_tls_ccert_verifydepth</a> for further details. </p> 15380 15381<p> This feature is available in Postfix 2.8 and later. </p> 15382 15383 15384</DD> 15385 15386<DT><b><a name="tlsproxy_tls_cert_file">tlsproxy_tls_cert_file</a> 15387(default: $<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a>)</b></DT><DD> 15388 15389<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server RSA certificate in PEM 15390format. This file may also contain the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15391private RSA key. See <a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a> for further details. </p> 15392 15393<p> This feature is available in Postfix 2.8 and later. </p> 15394 15395 15396</DD> 15397 15398<DT><b><a name="tlsproxy_tls_ciphers">tlsproxy_tls_ciphers</a> 15399(default: $<a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a>)</b></DT><DD> 15400 15401<p> The minimum TLS cipher grade that the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15402will use with opportunistic TLS encryption. See <a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> 15403for further details. </p> 15404 15405<p> This feature is available in Postfix 2.8 and later. </p> 15406 15407 15408</DD> 15409 15410<DT><b><a name="tlsproxy_tls_dcert_file">tlsproxy_tls_dcert_file</a> 15411(default: $<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>)</b></DT><DD> 15412 15413<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server DSA certificate in PEM 15414format. This file may also contain the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15415private DSA key. See <a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a> for further details. 15416</p> 15417 15418<p> This feature is available in Postfix 2.8 and later. </p> 15419 15420 15421</DD> 15422 15423<DT><b><a name="tlsproxy_tls_dh1024_param_file">tlsproxy_tls_dh1024_param_file</a> 15424(default: $<a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a>)</b></DT><DD> 15425 15426<p> File with DH parameters that the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15427should use with EDH ciphers. See <a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a> for 15428further details. </p> 15429 15430<p> This feature is available in Postfix 2.8 and later. </p> 15431 15432 15433</DD> 15434 15435<DT><b><a name="tlsproxy_tls_dh512_param_file">tlsproxy_tls_dh512_param_file</a> 15436(default: $<a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a>)</b></DT><DD> 15437 15438<p> File with DH parameters that the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15439should use with EDH ciphers. See <a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a> for 15440further details. </p> 15441 15442<p> This feature is available in Postfix 2.8 and later. </p> 15443 15444 15445</DD> 15446 15447<DT><b><a name="tlsproxy_tls_dkey_file">tlsproxy_tls_dkey_file</a> 15448(default: $<a href="postconf.5.html#smtpd_tls_dkey_file">smtpd_tls_dkey_file</a>)</b></DT><DD> 15449 15450<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server DSA private key in PEM 15451format. This file may be combined with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> 15452server DSA certificate file specified with $<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>. 15453See <a href="postconf.5.html#smtpd_tls_dkey_file">smtpd_tls_dkey_file</a> for further details. </p> 15454 15455<p> This feature is available in Postfix 2.8 and later. </p> 15456 15457 15458</DD> 15459 15460<DT><b><a name="tlsproxy_tls_eccert_file">tlsproxy_tls_eccert_file</a> 15461(default: $<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>)</b></DT><DD> 15462 15463<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server ECDSA certificate in 15464PEM format. This file may also contain the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> 15465server private ECDSA key. See <a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a> for further 15466details. </p> 15467 15468<p> This feature is available in Postfix 2.8 and later. </p> 15469 15470 15471</DD> 15472 15473<DT><b><a name="tlsproxy_tls_eckey_file">tlsproxy_tls_eckey_file</a> 15474(default: $<a href="postconf.5.html#smtpd_tls_eckey_file">smtpd_tls_eckey_file</a>)</b></DT><DD> 15475 15476<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server ECDSA private key in 15477PEM format. This file may be combined with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> 15478server ECDSA certificate file specified with $<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>. 15479See <a href="postconf.5.html#smtpd_tls_eckey_file">smtpd_tls_eckey_file</a> for further details. </p> 15480 15481<p> This feature is available in Postfix 2.8 and later. </p> 15482 15483 15484</DD> 15485 15486<DT><b><a name="tlsproxy_tls_eecdh_grade">tlsproxy_tls_eecdh_grade</a> 15487(default: $<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a>)</b></DT><DD> 15488 15489<p> The Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server security grade for ephemeral 15490elliptic-curve Diffie-Hellman (EECDH) key exchange. See 15491<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a> for further details. </p> 15492 15493<p> This feature is available in Postfix 2.8 and later. </p> 15494 15495 15496</DD> 15497 15498<DT><b><a name="tlsproxy_tls_exclude_ciphers">tlsproxy_tls_exclude_ciphers</a> 15499(default: $<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a>)</b></DT><DD> 15500 15501<p> List of ciphers or cipher types to exclude from the <a href="tlsproxy.8.html">tlsproxy(8)</a> 15502server cipher list at all TLS security levels. See 15503<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a> for further details. </p> 15504 15505<p> This feature is available in Postfix 2.8 and later. </p> 15506 15507 15508</DD> 15509 15510<DT><b><a name="tlsproxy_tls_fingerprint_digest">tlsproxy_tls_fingerprint_digest</a> 15511(default: $<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a>)</b></DT><DD> 15512 15513<p> The message digest algorithm used to construct client-certificate 15514fingerprints. See <a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_fingerprint_digest</a> for further details. 15515</p> 15516 15517<p> This feature is available in Postfix 2.8 and later. </p> 15518 15519 15520</DD> 15521 15522<DT><b><a name="tlsproxy_tls_key_file">tlsproxy_tls_key_file</a> 15523(default: $<a href="postconf.5.html#smtpd_tls_key_file">smtpd_tls_key_file</a>)</b></DT><DD> 15524 15525<p> File with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server RSA private key in PEM 15526format. This file may be combined with the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> 15527server RSA certificate file specified with $<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a>. 15528See <a href="postconf.5.html#smtpd_tls_key_file">smtpd_tls_key_file</a> for further details. </p> 15529 15530<p> This feature is available in Postfix 2.8 and later. </p> 15531 15532 15533</DD> 15534 15535<DT><b><a name="tlsproxy_tls_loglevel">tlsproxy_tls_loglevel</a> 15536(default: $<a href="postconf.5.html#smtpd_tls_loglevel">smtpd_tls_loglevel</a>)</b></DT><DD> 15537 15538<p> Enable additional Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server logging of TLS 15539activity. Each logging level also includes the information that 15540is logged at a lower logging level. See <a href="postconf.5.html#smtpd_tls_loglevel">smtpd_tls_loglevel</a> for 15541further details. </p> 15542 15543<p> This feature is available in Postfix 2.8 and later. </p> 15544 15545 15546</DD> 15547 15548<DT><b><a name="tlsproxy_tls_mandatory_ciphers">tlsproxy_tls_mandatory_ciphers</a> 15549(default: $<a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a>)</b></DT><DD> 15550 15551<p> The minimum TLS cipher grade that the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15552will use with mandatory TLS encryption. See <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> 15553for further details. </p> 15554 15555<p> This feature is available in Postfix 2.8 and later. </p> 15556 15557 15558</DD> 15559 15560<DT><b><a name="tlsproxy_tls_mandatory_exclude_ciphers">tlsproxy_tls_mandatory_exclude_ciphers</a> 15561(default: $<a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a>)</b></DT><DD> 15562 15563<p> Additional list of ciphers or cipher types to exclude from the 15564<a href="tlsproxy.8.html">tlsproxy(8)</a> server cipher list at mandatory TLS security levels. 15565See <a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> for further details. </p> 15566 15567<p> This feature is available in Postfix 2.8 and later. </p> 15568 15569 15570</DD> 15571 15572<DT><b><a name="tlsproxy_tls_mandatory_protocols">tlsproxy_tls_mandatory_protocols</a> 15573(default: $<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a>)</b></DT><DD> 15574 15575<p> The SSL/TLS protocols accepted by the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server 15576with mandatory TLS encryption. If the list is empty, the server 15577supports all available SSL/TLS protocol versions. See 15578<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> for further details. </p> 15579 15580<p> This feature is available in Postfix 2.8 and later. </p> 15581 15582 15583</DD> 15584 15585<DT><b><a name="tlsproxy_tls_protocols">tlsproxy_tls_protocols</a> 15586(default: $<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a>)</b></DT><DD> 15587 15588<p> List of TLS protocols that the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server will 15589exclude or include with opportunistic TLS encryption. See 15590<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> for further details. </p> 15591 15592<p> This feature is available in Postfix 2.8 and later. </p> 15593 15594 15595</DD> 15596 15597<DT><b><a name="tlsproxy_tls_req_ccert">tlsproxy_tls_req_ccert</a> 15598(default: $<a href="postconf.5.html#smtpd_tls_req_ccert">smtpd_tls_req_ccert</a>)</b></DT><DD> 15599 15600<p> With mandatory TLS encryption, require a trusted remote SMTP 15601client certificate in order to allow TLS connections to proceed. 15602See <a href="postconf.5.html#smtpd_tls_req_ccert">smtpd_tls_req_ccert</a> for further details. </p> 15603 15604<p> This feature is available in Postfix 2.8 and later. </p> 15605 15606 15607</DD> 15608 15609<DT><b><a name="tlsproxy_tls_security_level">tlsproxy_tls_security_level</a> 15610(default: $<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b></DT><DD> 15611 15612<p> The SMTP TLS security level for the Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server; 15613when a non-empty value is specified, this overrides the obsolete 15614parameters <a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> and <a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>. See 15615<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> for further details. </p> 15616 15617<p> This feature is available in Postfix 2.8 and later. </p> 15618 15619 15620</DD> 15621 15622<DT><b><a name="tlsproxy_tls_session_cache_timeout">tlsproxy_tls_session_cache_timeout</a> 15623(default: $<a href="postconf.5.html#smtpd_tls_session_cache_timeout">smtpd_tls_session_cache_timeout</a>)</b></DT><DD> 15624 15625<p> The expiration time of Postfix <a href="tlsproxy.8.html">tlsproxy(8)</a> server TLS session 15626cache information. A cache cleanup is performed periodically every 15627$<a href="postconf.5.html#smtpd_tls_session_cache_timeout">smtpd_tls_session_cache_timeout</a> seconds. See 15628<a href="postconf.5.html#smtpd_tls_session_cache_timeout">smtpd_tls_session_cache_timeout</a> for further details. </p> 15629 15630<p> This feature is available in Postfix 2.8 and later. </p> 15631 15632 15633</DD> 15634 15635<DT><b><a name="tlsproxy_use_tls">tlsproxy_use_tls</a> 15636(default: $<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b></DT><DD> 15637 15638<p> Opportunistic TLS: announce STARTTLS support to SMTP clients, 15639but do not require that clients use TLS encryption. See <a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> 15640for further details. </p> 15641 15642<p> This feature is available in Postfix 2.8 and later. </p> 15643 15644 15645</DD> 15646 15647<DT><b><a name="tlsproxy_watchdog_timeout">tlsproxy_watchdog_timeout</a> 15648(default: 10s)</b></DT><DD> 15649 15650<p> How much time a <a href="tlsproxy.8.html">tlsproxy(8)</a> process may take to process local 15651or remote I/O before it is terminated by a built-in watchdog timer. 15652This is a safety mechanism that prevents <a href="tlsproxy.8.html">tlsproxy(8)</a> from becoming 15653non-responsive due to a bug in Postfix itself or in system software. 15654To avoid false alarms and unnecessary cache corruption this limit 15655cannot be set under 10s. </p> 15656 15657<p> Specify a non-zero time value (an integral value plus an optional 15658one-letter suffix that specifies the time unit). Time units: s 15659(seconds), m (minutes), h (hours), d (days), w (weeks). </p> 15660 15661<p> This feature is available in Postfix 2.8. </p> 15662 15663 15664</DD> 15665 15666<DT><b><a name="trace_service_name">trace_service_name</a> 15667(default: trace)</b></DT><DD> 15668 15669<p> 15670The name of the trace service. This service is implemented by the 15671<a href="bounce.8.html">bounce(8)</a> daemon and maintains a record 15672of mail deliveries and produces a mail delivery report when verbose 15673delivery is requested with "<b>sendmail -v</b>". 15674</p> 15675 15676<p> 15677This feature is available in Postfix 2.1 and later. 15678</p> 15679 15680 15681</DD> 15682 15683<DT><b><a name="transport_delivery_slot_cost">transport_delivery_slot_cost</a> 15684(default: $<a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a>)</b></DT><DD> 15685 15686<p> A transport-specific override for the <a href="postconf.5.html#default_delivery_slot_cost">default_delivery_slot_cost</a> 15687parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15688the message delivery transport. </p> 15689 15690 15691</DD> 15692 15693<DT><b><a name="transport_delivery_slot_discount">transport_delivery_slot_discount</a> 15694(default: $<a href="postconf.5.html#default_delivery_slot_discount">default_delivery_slot_discount</a>)</b></DT><DD> 15695 15696<p> A transport-specific override for the <a href="postconf.5.html#default_delivery_slot_discount">default_delivery_slot_discount</a> 15697parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15698the message delivery transport. </p> 15699 15700 15701</DD> 15702 15703<DT><b><a name="transport_delivery_slot_loan">transport_delivery_slot_loan</a> 15704(default: $<a href="postconf.5.html#default_delivery_slot_loan">default_delivery_slot_loan</a>)</b></DT><DD> 15705 15706<p> A transport-specific override for the <a href="postconf.5.html#default_delivery_slot_loan">default_delivery_slot_loan</a> 15707parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15708the message delivery transport. </p> 15709 15710 15711</DD> 15712 15713<DT><b><a name="transport_destination_concurrency_failed_cohort_limit">transport_destination_concurrency_failed_cohort_limit</a> 15714(default: $<a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a>)</b></DT><DD> 15715 15716<p> A transport-specific override for the 15717<a href="postconf.5.html#default_destination_concurrency_failed_cohort_limit">default_destination_concurrency_failed_cohort_limit</a> parameter value, 15718where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message delivery 15719transport. </p> 15720 15721<p> This feature is available in Postfix 2.5 and later. </p> 15722 15723 15724</DD> 15725 15726<DT><b><a name="transport_destination_concurrency_limit">transport_destination_concurrency_limit</a> 15727(default: $<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a>)</b></DT><DD> 15728 15729<p> A transport-specific override for the 15730<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a> parameter value, where 15731<i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message delivery 15732transport. </p> 15733 15734 15735</DD> 15736 15737<DT><b><a name="transport_destination_concurrency_negative_feedback">transport_destination_concurrency_negative_feedback</a> 15738(default: $<a href="postconf.5.html#default_destination_concurrency_negative_feedback">default_destination_concurrency_negative_feedback</a>)</b></DT><DD> 15739 15740<p> A transport-specific override for the 15741<a href="postconf.5.html#default_destination_concurrency_negative_feedback">default_destination_concurrency_negative_feedback</a> parameter value, 15742where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message delivery 15743transport. </p> 15744 15745<p> This feature is available in Postfix 2.5 and later. </p> 15746 15747 15748</DD> 15749 15750<DT><b><a name="transport_destination_concurrency_positive_feedback">transport_destination_concurrency_positive_feedback</a> 15751(default: $<a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destination_concurrency_positive_feedback</a>)</b></DT><DD> 15752 15753<p> A transport-specific override for the 15754<a href="postconf.5.html#default_destination_concurrency_positive_feedback">default_destination_concurrency_positive_feedback</a> parameter value, 15755where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message delivery 15756transport. </p> 15757 15758<p> This feature is available in Postfix 2.5 and later. </p> 15759 15760 15761</DD> 15762 15763<DT><b><a name="transport_destination_rate_delay">transport_destination_rate_delay</a> 15764(default: $<a href="postconf.5.html#default_destination_rate_delay">default_destination_rate_delay</a>)</b></DT><DD> 15765 15766<p> A transport-specific override for the <a href="postconf.5.html#default_destination_rate_delay">default_destination_rate_delay</a> 15767parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15768the message delivery transport. </p> 15769 15770<p> This feature is available in Postfix 2.5 and later. </p> 15771 15772 15773</DD> 15774 15775<DT><b><a name="transport_destination_recipient_limit">transport_destination_recipient_limit</a> 15776(default: $<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a>)</b></DT><DD> 15777 15778<p> A transport-specific override for the 15779<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a> parameter value, where 15780<i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message delivery 15781transport. </p> 15782 15783 15784</DD> 15785 15786<DT><b><a name="transport_extra_recipient_limit">transport_extra_recipient_limit</a> 15787(default: $<a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipient_limit</a>)</b></DT><DD> 15788 15789<p> A transport-specific override for the <a href="postconf.5.html#default_extra_recipient_limit">default_extra_recipient_limit</a> 15790parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15791the message delivery transport. </p> 15792 15793 15794</DD> 15795 15796<DT><b><a name="transport_initial_destination_concurrency">transport_initial_destination_concurrency</a> 15797(default: $<a href="postconf.5.html#initial_destination_concurrency">initial_destination_concurrency</a>)</b></DT><DD> 15798 15799<p> A transport-specific override for the <a href="postconf.5.html#initial_destination_concurrency">initial_destination_concurrency</a> 15800parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15801the message delivery transport. </p> 15802 15803<p> This feature is available in Postfix 2.5 and later. </p> 15804 15805 15806</DD> 15807 15808<DT><b><a name="transport_maps">transport_maps</a> 15809(default: empty)</b></DT><DD> 15810 15811<p> 15812Optional lookup tables with mappings from recipient address to 15813(message delivery transport, next-hop destination). See <a href="transport.5.html">transport(5)</a> 15814for details. 15815</p> 15816 15817<p> 15818Specify zero or more "<a href="DATABASE_README.html">type:table</a>" lookup tables. If you use this 15819feature with local files, run "<b>postmap /etc/postfix/transport</b>" 15820after making a change. </p> 15821 15822<p> For safety reasons, as of Postfix 2.3 this feature does not 15823allow $number substitutions in regular expression maps. </p> 15824 15825<p> 15826Examples: 15827</p> 15828 15829<pre> 15830<a href="postconf.5.html#transport_maps">transport_maps</a> = dbm:/etc/postfix/transport 15831<a href="postconf.5.html#transport_maps">transport_maps</a> = hash:/etc/postfix/transport 15832</pre> 15833 15834 15835</DD> 15836 15837<DT><b><a name="transport_minimum_delivery_slots">transport_minimum_delivery_slots</a> 15838(default: $<a href="postconf.5.html#default_minimum_delivery_slots">default_minimum_delivery_slots</a>)</b></DT><DD> 15839 15840<p> A transport-specific override for the <a href="postconf.5.html#default_minimum_delivery_slots">default_minimum_delivery_slots</a> 15841parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15842the message delivery transport. </p> 15843 15844 15845</DD> 15846 15847<DT><b><a name="transport_recipient_limit">transport_recipient_limit</a> 15848(default: $<a href="postconf.5.html#default_recipient_limit">default_recipient_limit</a>)</b></DT><DD> 15849 15850<p> A transport-specific override for the <a href="postconf.5.html#default_recipient_limit">default_recipient_limit</a> 15851parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15852the message delivery transport. </p> 15853 15854 15855</DD> 15856 15857<DT><b><a name="transport_recipient_refill_delay">transport_recipient_refill_delay</a> 15858(default: $<a href="postconf.5.html#default_recipient_refill_delay">default_recipient_refill_delay</a>)</b></DT><DD> 15859 15860<p> A transport-specific override for the <a href="postconf.5.html#default_recipient_refill_delay">default_recipient_refill_delay</a> 15861parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15862the message delivery transport. </p> 15863 15864<p> This feature is available in Postfix 2.4 and later. </p> 15865 15866 15867</DD> 15868 15869<DT><b><a name="transport_recipient_refill_limit">transport_recipient_refill_limit</a> 15870(default: $<a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a>)</b></DT><DD> 15871 15872<p> A transport-specific override for the <a href="postconf.5.html#default_recipient_refill_limit">default_recipient_refill_limit</a> 15873parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of 15874the message delivery transport. </p> 15875 15876<p> This feature is available in Postfix 2.4 and later. </p> 15877 15878 15879</DD> 15880 15881<DT><b><a name="transport_retry_time">transport_retry_time</a> 15882(default: 60s)</b></DT><DD> 15883 15884<p> 15885The time between attempts by the Postfix queue manager to contact 15886a malfunctioning message delivery transport. 15887</p> 15888 15889<p> 15890Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 15891The default time unit is s (seconds). 15892</p> 15893 15894 15895</DD> 15896 15897<DT><b><a name="transport_time_limit">transport_time_limit</a> 15898(default: $<a href="postconf.5.html#command_time_limit">command_time_limit</a>)</b></DT><DD> 15899 15900<p> A transport-specific override for the <a href="postconf.5.html#command_time_limit">command_time_limit</a> parameter 15901value, where <i>transport</i> is the <a href="master.5.html">master.cf</a> name of the message 15902delivery transport. </p> 15903 15904 15905</DD> 15906 15907<DT><b><a name="trigger_timeout">trigger_timeout</a> 15908(default: 10s)</b></DT><DD> 15909 15910<p> 15911The time limit for sending a trigger to a Postfix daemon (for 15912example, the <a href="pickup.8.html">pickup(8)</a> or <a href="qmgr.8.html">qmgr(8)</a> daemon). This time limit prevents 15913programs from getting stuck when the mail system is under heavy 15914load. 15915</p> 15916 15917<p> 15918Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks). 15919The default time unit is s (seconds). 15920</p> 15921 15922 15923</DD> 15924 15925<DT><b><a name="undisclosed_recipients_header">undisclosed_recipients_header</a> 15926(default: see "postconf -d" output)</b></DT><DD> 15927 15928<p> 15929Message header that the Postfix <a href="cleanup.8.html">cleanup(8)</a> server inserts when a 15930message contains no To: or Cc: message header. With Postfix 2.8 15931and later, the default value is empty. With Postfix 2.4-2.7, 15932specify an empty value to disable this feature. </p> 15933 15934<p> Example: </p> 15935 15936<pre> 15937# Default value before Postfix 2.8. 15938# Note: the ":" and ";" are both required. 15939<a href="postconf.5.html#undisclosed_recipients_header">undisclosed_recipients_header</a> = To: undisclosed-recipients:; 15940</pre> 15941 15942 15943</DD> 15944 15945<DT><b><a name="unknown_address_reject_code">unknown_address_reject_code</a> 15946(default: 450)</b></DT><DD> 15947 15948<p> 15949The numerical Postfix SMTP server response code when a sender or 15950recipient address is rejected by the <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> 15951or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a> restriction. The response is 15952always 450 in case of a temporary DNS error. 15953</p> 15954 15955<p> 15956Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 15957</p> 15958 15959 15960</DD> 15961 15962<DT><b><a name="unknown_address_tempfail_action">unknown_address_tempfail_action</a> 15963(default: $<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b></DT><DD> 15964 15965<p> The Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> 15966or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a> fail due to a temporary error 15967condition. Specify "defer" to defer the remote SMTP client request 15968immediately. With the default "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" action, the Postfix 15969SMTP server continues to look for opportunities to reject mail, and 15970defers the client request only if it would otherwise be accepted. 15971</p> 15972 15973<p> This feature is available in Postfix 2.6 and later. </p> 15974 15975 15976</DD> 15977 15978<DT><b><a name="unknown_client_reject_code">unknown_client_reject_code</a> 15979(default: 450)</b></DT><DD> 15980 15981<p> 15982The numerical Postfix SMTP server response code when a client 15983without valid address <=> name mapping is rejected by the 15984<a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> restriction. The SMTP server always replies 15985with 450 when the mapping failed due to a temporary error condition. 15986</p> 15987 15988<p> 15989Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 15990</p> 15991 15992 15993</DD> 15994 15995<DT><b><a name="unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a> 15996(default: $<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b></DT><DD> 15997 15998<p> The Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> 15999fails due to an temporary error condition. Specify "defer" to defer 16000the remote SMTP client request immediately. With the default 16001"<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" action, the Postfix SMTP server continues to look 16002for opportunities to reject mail, and defers the client request 16003only if it would otherwise be accepted. </p> 16004 16005<p> This feature is available in Postfix 2.6 and later. </p> 16006 16007 16008</DD> 16009 16010<DT><b><a name="unknown_hostname_reject_code">unknown_hostname_reject_code</a> 16011(default: 450)</b></DT><DD> 16012 16013<p> 16014The numerical Postfix SMTP server response code when the hostname 16015specified with the HELO or EHLO command is rejected by the 16016<a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> restriction. 16017</p> 16018 16019<p> 16020Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 16021</p> 16022 16023 16024</DD> 16025 16026<DT><b><a name="unknown_local_recipient_reject_code">unknown_local_recipient_reject_code</a> 16027(default: 550)</b></DT><DD> 16028 16029<p> 16030The numerical Postfix SMTP server response code when a recipient 16031address is local, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> specifies a list of 16032lookup tables that does not match the recipient. A recipient 16033address is local when its domain matches $<a href="postconf.5.html#mydestination">mydestination</a>, 16034$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> or $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>. 16035</p> 16036 16037<p> 16038The default setting is 550 (reject mail) but it is safer to initially 16039use 450 (try again later) so you have time to find out if your 16040<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> settings are OK. 16041</p> 16042 16043<p> 16044Example: 16045</p> 16046 16047<pre> 16048<a href="postconf.5.html#unknown_local_recipient_reject_code">unknown_local_recipient_reject_code</a> = 450 16049</pre> 16050 16051<p> 16052This feature is available in Postfix 2.0 and later. 16053</p> 16054 16055 16056</DD> 16057 16058<DT><b><a name="unknown_relay_recipient_reject_code">unknown_relay_recipient_reject_code</a> 16059(default: 550)</b></DT><DD> 16060 16061<p> 16062The numerical Postfix SMTP server reply code when a recipient 16063address matches $<a href="postconf.5.html#relay_domains">relay_domains</a>, and <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> specifies 16064a list of lookup tables that does not match the recipient address. 16065</p> 16066 16067<p> 16068This feature is available in Postfix 2.0 and later. 16069</p> 16070 16071 16072</DD> 16073 16074<DT><b><a name="unknown_virtual_alias_reject_code">unknown_virtual_alias_reject_code</a> 16075(default: 550)</b></DT><DD> 16076 16077<p> 16078The SMTP server reply code when a recipient address matches 16079$<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, and $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> specifies a list 16080of lookup tables that does not match the recipient address. 16081</p> 16082 16083<p> 16084This feature is available in Postfix 2.0 and later. 16085</p> 16086 16087 16088</DD> 16089 16090<DT><b><a name="unknown_virtual_mailbox_reject_code">unknown_virtual_mailbox_reject_code</a> 16091(default: 550)</b></DT><DD> 16092 16093<p> 16094The SMTP server reply code when a recipient address matches 16095$<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, and $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> specifies a list 16096of lookup tables that does not match the recipient address. 16097</p> 16098 16099<p> 16100This feature is available in Postfix 2.0 and later. 16101</p> 16102 16103 16104</DD> 16105 16106<DT><b><a name="unverified_recipient_defer_code">unverified_recipient_defer_code</a> 16107(default: 450)</b></DT><DD> 16108 16109<p> 16110The numerical Postfix SMTP server response when a recipient address 16111probe fails due to a temporary error condition. 16112</p> 16113 16114<p> 16115Unlike elsewhere in Postfix, you can specify 250 in order to 16116accept the address anyway. 16117</p> 16118 16119<p> 16120Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 16121</p> 16122 16123<p> 16124This feature is available in Postfix 2.6 and later. 16125</p> 16126 16127 16128</DD> 16129 16130<DT><b><a name="unverified_recipient_reject_code">unverified_recipient_reject_code</a> 16131(default: 450)</b></DT><DD> 16132 16133<p> 16134The numerical Postfix SMTP server response when a recipient address 16135is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restriction. 16136</p> 16137 16138<p> 16139Unlike elsewhere in Postfix, you can specify 250 in order to 16140accept the address anyway. 16141</p> 16142 16143<p> 16144Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 16145</p> 16146 16147<p> 16148This feature is available in Postfix 2.1 and later. 16149</p> 16150 16151 16152</DD> 16153 16154<DT><b><a name="unverified_recipient_reject_reason">unverified_recipient_reject_reason</a> 16155(default: empty)</b></DT><DD> 16156 16157<p> The Postfix SMTP server's reply when rejecting mail with 16158<a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>. Do not include the numeric SMTP reply 16159code or the enhanced status code. By default, the response includes 16160actual address verification details. 16161 16162<p> Example: </p> 16163 16164<pre> 16165<a href="postconf.5.html#unverified_recipient_reject_reason">unverified_recipient_reject_reason</a> = Recipient address lookup failed 16166</pre> 16167 16168<p> This feature is available in Postfix 2.6 and later. </p> 16169 16170 16171</DD> 16172 16173<DT><b><a name="unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a> 16174(default: $<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b></DT><DD> 16175 16176<p> The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> 16177fails due to a temporary error condition. Specify "defer" to defer 16178the remote SMTP client request immediately. With the default 16179"<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" action, the Postfix SMTP server continues to look 16180for opportunities to reject mail, and defers the client request 16181only if it would otherwise be accepted. </p> 16182 16183<p> This feature is available in Postfix 2.6 and later. </p> 16184 16185 16186</DD> 16187 16188<DT><b><a name="unverified_sender_defer_code">unverified_sender_defer_code</a> 16189(default: 450)</b></DT><DD> 16190 16191<p> 16192The numerical Postfix SMTP server response code when a sender address 16193probe fails due to a temporary error condition. 16194</p> 16195 16196<p> 16197Unlike elsewhere in Postfix, you can specify 250 in order to 16198accept the address anyway. 16199</p> 16200 16201<p> 16202Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 16203</p> 16204 16205<p> 16206This feature is available in Postfix 2.6 and later. 16207</p> 16208 16209 16210</DD> 16211 16212<DT><b><a name="unverified_sender_reject_code">unverified_sender_reject_code</a> 16213(default: 450)</b></DT><DD> 16214 16215<p> 16216The numerical Postfix SMTP server response code when a recipient 16217address is rejected by the <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> restriction. 16218</p> 16219 16220<p> 16221Unlike elsewhere in Postfix, you can specify 250 in order to 16222accept the address anyway. 16223</p> 16224 16225<p> 16226Do not change this unless you have a complete understanding of <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>. 16227</p> 16228 16229<p> 16230This feature is available in Postfix 2.1 and later. 16231</p> 16232 16233 16234</DD> 16235 16236<DT><b><a name="unverified_sender_reject_reason">unverified_sender_reject_reason</a> 16237(default: empty)</b></DT><DD> 16238 16239<p> The Postfix SMTP server's reply when rejecting mail with 16240<a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>. Do not include the numeric SMTP reply 16241code or the enhanced status code. By default, the response includes 16242actual address verification details. 16243 16244<p> Example: </p> 16245 16246<pre> 16247<a href="postconf.5.html#unverified_sender_reject_reason">unverified_sender_reject_reason</a> = Sender address lookup failed 16248</pre> 16249 16250<p> This feature is available in Postfix 2.6 and later. </p> 16251 16252 16253</DD> 16254 16255<DT><b><a name="unverified_sender_tempfail_action">unverified_sender_tempfail_action</a> 16256(default: $<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b></DT><DD> 16257 16258<p> The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> 16259fails due to a temporary error condition. Specify "defer" to defer 16260the remote SMTP client request immediately. With the default 16261"<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" action, the Postfix SMTP server continues to look 16262for opportunities to reject mail, and defers the client request 16263only if it would otherwise be accepted. </p> 16264 16265<p> This feature is available in Postfix 2.6 and later. </p> 16266 16267 16268</DD> 16269 16270<DT><b><a name="verp_delimiter_filter">verp_delimiter_filter</a> 16271(default: -=+)</b></DT><DD> 16272 16273<p> 16274The characters Postfix accepts as VERP delimiter characters on the 16275Postfix <a href="sendmail.1.html">sendmail(1)</a> command line and in SMTP commands. 16276</p> 16277 16278<p> 16279This feature is available in Postfix 1.1 and later. 16280</p> 16281 16282 16283</DD> 16284 16285<DT><b><a name="virtual_alias_domains">virtual_alias_domains</a> 16286(default: $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>)</b></DT><DD> 16287 16288<p> Postfix is final destination for the specified list of virtual 16289alias domains, that is, domains for which all addresses are aliased 16290to addresses in other local or remote domains. The SMTP server 16291validates recipient addresses with $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> and rejects 16292non-existent recipients. See also the <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a> class 16293in the <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> file </p> 16294 16295<p> 16296This feature is available in Postfix 2.0 and later. The default 16297value is backwards compatible with Postfix version 1.1. 16298</p> 16299 16300<p> 16301The default value is $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> so that you can keep all 16302information about <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domains</a> in one place. If you have 16303many users, it is better to separate information that changes more 16304frequently (virtual address -> local or remote address mapping) 16305from information that changes less frequently (the list of virtual 16306domain names). 16307</p> 16308 16309<p> Specify a list of host or domain names, "/file/name" or 16310"<a href="DATABASE_README.html">type:table</a>" patterns, separated by commas and/or whitespace. A 16311"/file/name" pattern is replaced by its contents; a "<a href="DATABASE_README.html">type:table</a>" 16312lookup table is matched when a table entry matches a lookup string 16313(the lookup result is ignored). Continue long lines by starting 16314the next line with whitespace. Specify "!pattern" to exclude a host 16315or domain name from the list. The form "!/file/name" is supported 16316only in Postfix version 2.4 and later. </p> 16317 16318<p> 16319See also the <a href="VIRTUAL_README.html">VIRTUAL_README</a> and <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> documents 16320for further information. 16321</p> 16322 16323<p> 16324Example: 16325</p> 16326 16327<pre> 16328<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> = virtual1.tld virtual2.tld 16329</pre> 16330 16331 16332</DD> 16333 16334<DT><b><a name="virtual_alias_expansion_limit">virtual_alias_expansion_limit</a> 16335(default: 1000)</b></DT><DD> 16336 16337<p> 16338The maximal number of addresses that virtual alias expansion produces 16339from each original recipient. 16340</p> 16341 16342<p> 16343This feature is available in Postfix 2.1 and later. 16344</p> 16345 16346 16347</DD> 16348 16349<DT><b><a name="virtual_alias_maps">virtual_alias_maps</a> 16350(default: $<a href="postconf.5.html#virtual_maps">virtual_maps</a>)</b></DT><DD> 16351 16352<p> 16353Optional lookup tables that alias specific mail addresses or domains 16354to other local or remote address. The table format and lookups 16355are documented in <a href="virtual.5.html">virtual(5)</a>. For an overview of Postfix address 16356manipulations see the <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a> document. 16357</p> 16358 16359<p> 16360This feature is available in Postfix 2.0 and later. The default 16361value is backwards compatible with Postfix version 1.1. 16362</p> 16363 16364<p> 16365If you use this feature with indexed files, run "<b>postmap 16366/etc/postfix/virtual</b>" after changing the file. 16367</p> 16368 16369<p> 16370Examples: 16371</p> 16372 16373<pre> 16374<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> = dbm:/etc/postfix/virtual 16375<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> = hash:/etc/postfix/virtual 16376</pre> 16377 16378 16379</DD> 16380 16381<DT><b><a name="virtual_alias_recursion_limit">virtual_alias_recursion_limit</a> 16382(default: 1000)</b></DT><DD> 16383 16384<p> 16385The maximal nesting depth of virtual alias expansion. Currently 16386the recursion limit is applied only to the left branch of the 16387expansion graph, so the depth of the tree can in the worst case 16388reach the sum of the expansion and recursion limits. This may 16389change in the future. 16390</p> 16391 16392<p> 16393This feature is available in Postfix 2.1 and later. 16394</p> 16395 16396 16397</DD> 16398 16399<DT><b><a name="virtual_destination_concurrency_limit">virtual_destination_concurrency_limit</a> 16400(default: $<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concurrency_limit</a>)</b></DT><DD> 16401 16402<p> The maximal number of parallel deliveries to the same destination 16403via the virtual message delivery transport. This limit is enforced 16404by the queue manager. The message delivery transport name is the 16405first field in the entry in the <a href="master.5.html">master.cf</a> file. </p> 16406 16407 16408</DD> 16409 16410<DT><b><a name="virtual_destination_recipient_limit">virtual_destination_recipient_limit</a> 16411(default: $<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipient_limit</a>)</b></DT><DD> 16412 16413<p> The maximal number of recipients per message for the virtual 16414message delivery transport. This limit is enforced by the queue 16415manager. The message delivery transport name is the first field in 16416the entry in the <a href="master.5.html">master.cf</a> file. </p> 16417 16418<p> Setting this parameter to a value of 1 changes the meaning of 16419<a href="postconf.5.html#virtual_destination_concurrency_limit">virtual_destination_concurrency_limit</a> from concurrency per domain 16420into concurrency per recipient. </p> 16421 16422 16423</DD> 16424 16425<DT><b><a name="virtual_gid_maps">virtual_gid_maps</a> 16426(default: empty)</b></DT><DD> 16427 16428<p> 16429Lookup tables with the per-recipient group ID for <a href="virtual.8.html">virtual(8)</a> mailbox 16430delivery. 16431</p> 16432 16433<p> 16434In a lookup table, specify a left-hand side of "@domain.tld" to 16435match any user in the specified domain that does not have a specific 16436"user@domain.tld" entry. 16437</p> 16438 16439<p> 16440When a recipient address has an optional address extension 16441(user+foo@domain.tld), the <a href="virtual.8.html">virtual(8)</a> delivery agent looks up 16442the full address first, and when the lookup fails, it looks up the 16443unextended address (user@domain.tld). 16444</p> 16445 16446<p> 16447Note 1: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent disallows 16448regular expression substitution of $1 etc. in regular expression 16449lookup tables, because that would open a security hole. 16450</p> 16451 16452<p> 16453Note 2: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent will 16454silently ignore requests to use the <a href="proxymap.8.html">proxymap(8)</a> server. Instead 16455it will open the table directly. Before Postfix version 2.2, the 16456<a href="virtual.8.html">virtual(8)</a> delivery agent will terminate with a fatal error. 16457</p> 16458 16459 16460</DD> 16461 16462<DT><b><a name="virtual_mailbox_base">virtual_mailbox_base</a> 16463(default: empty)</b></DT><DD> 16464 16465<p> 16466A prefix that the <a href="virtual.8.html">virtual(8)</a> delivery agent prepends to all pathname 16467results from $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> table lookups. This is a safety 16468measure to ensure that an out of control map doesn't litter the 16469file system with mailboxes. While <a href="postconf.5.html#virtual_mailbox_base">virtual_mailbox_base</a> could be 16470set to "/", this setting isn't recommended. 16471</p> 16472 16473<p> 16474Example: 16475</p> 16476 16477<pre> 16478<a href="postconf.5.html#virtual_mailbox_base">virtual_mailbox_base</a> = /var/mail 16479</pre> 16480 16481 16482</DD> 16483 16484<DT><b><a name="virtual_mailbox_domains">virtual_mailbox_domains</a> 16485(default: $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>)</b></DT><DD> 16486 16487<p> Postfix is final destination for the specified list of domains; 16488mail is delivered via the $<a href="postconf.5.html#virtual_transport">virtual_transport</a> mail delivery transport. 16489By default this is the Postfix <a href="virtual.8.html">virtual(8)</a> delivery agent. The SMTP 16490server validates recipient addresses with $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> 16491and rejects mail for non-existent recipients. See also the virtual 16492mailbox domain class in the <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> file. </p> 16493 16494<p> This parameter expects the same syntax as the <a href="postconf.5.html#mydestination">mydestination</a> 16495configuration parameter. </p> 16496 16497<p> 16498This feature is available in Postfix 2.0 and later. The default 16499value is backwards compatible with Postfix version 1.1. 16500</p> 16501 16502 16503</DD> 16504 16505<DT><b><a name="virtual_mailbox_limit">virtual_mailbox_limit</a> 16506(default: 51200000)</b></DT><DD> 16507 16508<p> 16509The maximal size in bytes of an individual <a href="virtual.8.html">virtual(8)</a> mailbox or 16510maildir file, or zero (no limit). </p> 16511 16512 16513</DD> 16514 16515<DT><b><a name="virtual_mailbox_lock">virtual_mailbox_lock</a> 16516(default: see "postconf -d" output)</b></DT><DD> 16517 16518<p> 16519How to lock a UNIX-style <a href="virtual.8.html">virtual(8)</a> mailbox before attempting 16520delivery. For a list of available file locking methods, use the 16521"<b>postconf -l</b>" command. 16522</p> 16523 16524<p> 16525This setting is ignored with <b>maildir</b> style delivery, because 16526such deliveries are safe without application-level locks. 16527</p> 16528 16529<p> 16530Note 1: the <b>dotlock</b> method requires that the recipient UID 16531or GID has write access to the parent directory of the recipient's 16532mailbox file. 16533</p> 16534 16535<p> 16536Note 2: the default setting of this parameter is system dependent. 16537</p> 16538 16539 16540</DD> 16541 16542<DT><b><a name="virtual_mailbox_maps">virtual_mailbox_maps</a> 16543(default: empty)</b></DT><DD> 16544 16545<p> 16546Optional lookup tables with all valid addresses in the domains that 16547match $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>. 16548</p> 16549 16550<p> 16551In a lookup table, specify a left-hand side of "@domain.tld" to 16552match any user in the specified domain that does not have a specific 16553"user@domain.tld" entry. 16554</p> 16555 16556<p> 16557The <a href="virtual.8.html">virtual(8)</a> delivery agent uses this table to look up the 16558per-recipient mailbox or maildir pathname. If the lookup result 16559ends in a slash ("/"), maildir-style delivery is carried out, 16560otherwise the path is assumed to specify a UNIX-style mailbox file. 16561Note that $<a href="postconf.5.html#virtual_mailbox_base">virtual_mailbox_base</a> is unconditionally prepended to 16562this path. 16563</p> 16564 16565<p> 16566When a recipient address has an optional address extension 16567(user+foo@domain.tld), the <a href="virtual.8.html">virtual(8)</a> delivery agent looks up 16568the full address first, and when the lookup fails, it looks up the 16569unextended address (user@domain.tld). 16570</p> 16571 16572<p> 16573Note 1: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent disallows 16574regular expression substitution of $1 etc. in regular expression 16575lookup tables, because that would open a security hole. 16576</p> 16577 16578<p> 16579Note 2: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent will 16580silently ignore requests to use the <a href="proxymap.8.html">proxymap(8)</a> server. Instead 16581it will open the table directly. Before Postfix version 2.2, the 16582<a href="virtual.8.html">virtual(8)</a> delivery agent will terminate with a fatal error. 16583</p> 16584 16585 16586</DD> 16587 16588<DT><b><a name="virtual_maps">virtual_maps</a> 16589(default: empty)</b></DT><DD> 16590 16591<p> Optional lookup tables with a) names of domains for which all 16592addresses are aliased to addresses in other local or remote domains, 16593and b) addresses that are aliased to addresses in other local or 16594remote domains. Available before Postfix version 2.0. With Postfix 16595version 2.0 and later, this is replaced by separate controls: <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> 16596and <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>. </p> 16597 16598 16599</DD> 16600 16601<DT><b><a name="virtual_minimum_uid">virtual_minimum_uid</a> 16602(default: 100)</b></DT><DD> 16603 16604<p> 16605The minimum user ID value that the <a href="virtual.8.html">virtual(8)</a> delivery agent accepts 16606as a result from $<a href="postconf.5.html#virtual_uid_maps">virtual_uid_maps</a> table lookup. Returned 16607values less than this will be rejected, and the message will be 16608deferred. 16609</p> 16610 16611 16612</DD> 16613 16614<DT><b><a name="virtual_transport">virtual_transport</a> 16615(default: virtual)</b></DT><DD> 16616 16617<p> 16618The default mail delivery transport and next-hop destination for 16619final delivery to domains listed with $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>. 16620This information can be overruled with the <a href="transport.5.html">transport(5)</a> table. 16621</p> 16622 16623<p> 16624Specify a string of the form <i>transport:nexthop</i>, where <i>transport</i> 16625is the name of a mail delivery transport defined in <a href="master.5.html">master.cf</a>. 16626The <i>:nexthop</i> destination is optional; its syntax is documented 16627in the manual page of the corresponding delivery agent. 16628</p> 16629 16630<p> 16631This feature is available in Postfix 2.0 and later. 16632</p> 16633 16634 16635</DD> 16636 16637<DT><b><a name="virtual_uid_maps">virtual_uid_maps</a> 16638(default: empty)</b></DT><DD> 16639 16640<p> 16641Lookup tables with the per-recipient user ID that the <a href="virtual.8.html">virtual(8)</a> 16642delivery agent uses while writing to the recipient's mailbox. 16643</p> 16644 16645<p> 16646In a lookup table, specify a left-hand side of "@domain.tld" 16647to match any user in the specified domain that does not have a 16648specific "user@domain.tld" entry. 16649</p> 16650 16651<p> 16652When a recipient address has an optional address extension 16653(user+foo@domain.tld), the <a href="virtual.8.html">virtual(8)</a> delivery agent looks up 16654the full address first, and when the lookup fails, it looks up the 16655unextended address (user@domain.tld). 16656</p> 16657 16658<p> 16659Note 1: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent disallows 16660regular expression substitution of $1 etc. in regular expression 16661lookup tables, because that would open a security hole. 16662</p> 16663 16664<p> 16665Note 2: for security reasons, the <a href="virtual.8.html">virtual(8)</a> delivery agent will 16666silently ignore requests to use the <a href="proxymap.8.html">proxymap(8)</a> server. Instead 16667it will open the table directly. Before Postfix version 2.2, the 16668<a href="virtual.8.html">virtual(8)</a> delivery agent will terminate with a fatal error. 16669</p> 16670 16671 16672</DD> 16673 16674</dl> 16675 16676</body> 16677 16678</html> 16679
