1<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3<html> <head> 4<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 5<title> Postfix manual - smtp(8) </title> 6</head> <body> <pre> 7SMTP(8) SMTP(8) 8 9<b>NAME</b> 10 smtp - Postfix SMTP+LMTP client 11 12<b>SYNOPSIS</b> 13 <b>smtp</b> [generic Postfix daemon options] 14 15<b>DESCRIPTION</b> 16 The Postfix SMTP+LMTP client implements the SMTP and LMTP 17 mail delivery protocols. It processes message delivery 18 requests from the queue manager. Each request specifies a 19 queue file, a sender address, a domain or host to deliver 20 to, and recipient information. This program expects to be 21 run from the <a href="master.8.html"><b>master</b>(8)</a> process manager. 22 23 The SMTP+LMTP client updates the queue file and marks 24 recipients as finished, or it informs the queue manager 25 that delivery should be tried again at a later time. 26 Delivery status reports are sent to the <a href="bounce.8.html"><b>bounce</b>(8)</a>, 27 <a href="defer.8.html"><b>defer</b>(8)</a> or <a href="trace.8.html"><b>trace</b>(8)</a> daemon as appropriate. 28 29 The SMTP+LMTP client looks up a list of mail exchanger 30 addresses for the destination host, sorts the list by 31 preference, and connects to each listed address until it 32 finds a server that responds. 33 34 When a server is not reachable, or when mail delivery 35 fails due to a recoverable error condition, the SMTP+LMTP 36 client will try to deliver the mail to an alternate host. 37 38 After a successful mail transaction, a connection may be 39 saved to the <a href="scache.8.html"><b>scache</b>(8)</a> connection cache server, so that it 40 may be used by any SMTP+LMTP client for a subsequent 41 transaction. 42 43 By default, connection caching is enabled temporarily for 44 destinations that have a high volume of mail in the active 45 queue. Connection caching can be enabled permanently for 46 specific destinations. 47 48<b>SMTP DESTINATION SYNTAX</b> 49 SMTP destinations have the following form: 50 51 <i>domainname</i> 52 53 <i>domainname</i>:<i>port</i> 54 Look up the mail exchangers for the specified 55 domain, and connect to the specified port (default: 56 <b>smtp</b>). 57 58 [<i>hostname</i>] 59 60 [<i>hostname</i>]:<i>port</i> 61 Look up the address(es) of the specified host, and 62 connect to the specified port (default: <b>smtp</b>). 63 64 [<i>address</i>] 65 66 [<i>address</i>]:<i>port</i> 67 Connect to the host at the specified address, and 68 connect to the specified port (default: <b>smtp</b>). An 69 IPv6 address must be formatted as [<b>ipv6</b>:<i>address</i>]. 70 71<b>LMTP DESTINATION SYNTAX</b> 72 LMTP destinations have the following form: 73 74 <b>unix</b>:<i>pathname</i> 75 Connect to the local UNIX-domain server that is 76 bound to the specified <i>pathname</i>. If the process 77 runs chrooted, an absolute pathname is interpreted 78 relative to the Postfix queue directory. 79 80 <b>inet</b>:<i>hostname</i> 81 82 <b>inet:</b><i>hostname</i>:<i>port</i> 83 84 <b>inet</b>:[<i>address</i>] 85 86 <b>inet</b>:[<i>address</i>]:<i>port</i> 87 Connect to the specified TCP port on the specified 88 local or remote host. If no port is specified, con- 89 nect to the port defined as <b>lmtp</b> in <b>services</b>(4). 90 If no such service is found, the <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a></b> con- 91 figuration parameter (default value of 24) will be 92 used. An IPv6 address must be formatted as 93 [<b>ipv6</b>:<i>address</i>]. 94 95<b>SECURITY</b> 96 The SMTP+LMTP client is moderately security-sensitive. It 97 talks to SMTP or LMTP servers and to DNS servers on the 98 network. The SMTP+LMTP client can be run chrooted at fixed 99 low privilege. 100 101<b>STANDARDS</b> 102 <a href="http://tools.ietf.org/html/rfc821">RFC 821</a> (SMTP protocol) 103 <a href="http://tools.ietf.org/html/rfc822">RFC 822</a> (ARPA Internet Text Messages) 104 <a href="http://tools.ietf.org/html/rfc1651">RFC 1651</a> (SMTP service extensions) 105 <a href="http://tools.ietf.org/html/rfc1652">RFC 1652</a> (8bit-MIME transport) 106 <a href="http://tools.ietf.org/html/rfc1870">RFC 1870</a> (Message Size Declaration) 107 <a href="http://tools.ietf.org/html/rfc2033">RFC 2033</a> (LMTP protocol) 108 <a href="http://tools.ietf.org/html/rfc2034">RFC 2034</a> (SMTP Enhanced Error Codes) 109 <a href="http://tools.ietf.org/html/rfc2045">RFC 2045</a> (MIME: Format of Internet Message Bodies) 110 <a href="http://tools.ietf.org/html/rfc2046">RFC 2046</a> (MIME: Media Types) 111 <a href="http://tools.ietf.org/html/rfc2554">RFC 2554</a> (AUTH command) 112 <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a> (SMTP protocol) 113 <a href="http://tools.ietf.org/html/rfc2920">RFC 2920</a> (SMTP Pipelining) 114 <a href="http://tools.ietf.org/html/rfc3207">RFC 3207</a> (STARTTLS command) 115 <a href="http://tools.ietf.org/html/rfc3461">RFC 3461</a> (SMTP DSN Extension) 116 <a href="http://tools.ietf.org/html/rfc3463">RFC 3463</a> (Enhanced Status Codes) 117 <a href="http://tools.ietf.org/html/rfc4954">RFC 4954</a> (AUTH command) 118 <a href="http://tools.ietf.org/html/rfc5321">RFC 5321</a> (SMTP protocol) 119 120<b>DIAGNOSTICS</b> 121 Problems and transactions are logged to <b>syslogd</b>(8). Cor- 122 rupted message files are marked so that the queue manager 123 can move them to the <b>corrupt</b> queue for further inspection. 124 125 Depending on the setting of the <b><a href="postconf.5.html#notify_classes">notify_classes</a></b> parameter, 126 the postmaster is notified of bounces, protocol problems, 127 and of other trouble. 128 129<b>BUGS</b> 130 SMTP and LMTP connection caching does not work with TLS. 131 The necessary support for TLS object passivation and re- 132 activation does not exist without closing the session, 133 which defeats the purpose. 134 135 SMTP and LMTP connection caching assumes that SASL creden- 136 tials are valid for all destinations that map onto the 137 same IP address and TCP port. 138 139<b>CONFIGURATION PARAMETERS</b> 140 Before Postfix version 2.3, the LMTP client is a separate 141 program that implements only a subset of the functionality 142 available with SMTP: there is no support for TLS, and con- 143 nections are cached in-process, making it ineffective when 144 the client is used for multiple domains. 145 146 Most smtp_<i>xxx</i> configuration parameters have an lmtp_<i>xxx</i> 147 "mirror" parameter for the equivalent LMTP feature. This 148 document describes only those LMTP-related parameters that 149 aren't simply "mirror" parameters. 150 151 Changes to <a href="postconf.5.html"><b>main.cf</b></a> are picked up automatically, as <a href="smtp.8.html"><b>smtp</b>(8)</a> 152 processes run for only a limited amount of time. Use the 153 command "<b>postfix reload</b>" to speed up a change. 154 155 The text below provides only a parameter summary. See 156 <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples. 157 158<b>COMPATIBILITY CONTROLS</b> 159 <b><a href="postconf.5.html#ignore_mx_lookup_error">ignore_mx_lookup_error</a> (no)</b> 160 Ignore DNS MX lookups that produce no response. 161 162 <b><a href="postconf.5.html#smtp_always_send_ehlo">smtp_always_send_ehlo</a> (yes)</b> 163 Always send EHLO at the start of an SMTP session. 164 165 <b><a href="postconf.5.html#smtp_never_send_ehlo">smtp_never_send_ehlo</a> (no)</b> 166 Never send EHLO at the start of an SMTP session. 167 168 <b><a href="postconf.5.html#smtp_defer_if_no_mx_address_found">smtp_defer_if_no_mx_address_found</a> (no)</b> 169 Defer mail delivery when no MX record resolves to 170 an IP address. 171 172 <b><a href="postconf.5.html#smtp_line_length_limit">smtp_line_length_limit</a> (998)</b> 173 The maximal length of message header and body lines 174 that Postfix will send via SMTP. 175 176 <b><a href="postconf.5.html#smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> (10s)</b> 177 How long the Postfix SMTP client pauses before 178 sending ".<CR><LF>" in order to work around the PIX 179 firewall "<CR><LF>.<CR><LF>" bug. 180 181 <b><a href="postconf.5.html#smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> (500s)</b> 182 How long a message must be queued before the Post- 183 fix SMTP client turns on the PIX firewall 184 "<CR><LF>.<CR><LF>" bug workaround for delivery 185 through firewalls with "smtp fixup" mode turned on. 186 187 <b><a href="postconf.5.html#smtp_pix_workarounds">smtp_pix_workarounds</a> (disable_esmtp, delay_dotcrlf)</b> 188 A list that specifies zero or more workarounds for 189 CISCO PIX firewall bugs. 190 191 <b><a href="postconf.5.html#smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> (empty)</b> 192 Lookup tables, indexed by the remote SMTP server 193 address, with per-destination workarounds for CISCO 194 PIX firewall bugs. 195 196 <b><a href="postconf.5.html#smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a> (yes)</b> 197 Quote addresses in Postfix SMTP client MAIL FROM 198 and RCPT TO commands as required by <a href="http://tools.ietf.org/html/rfc5321">RFC 5321</a>. 199 200 <b><a href="postconf.5.html#smtp_reply_filter">smtp_reply_filter</a> (empty)</b> 201 A mechanism to transform replies from remote SMTP 202 servers one line at a time. 203 204 <b><a href="postconf.5.html#smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> (yes)</b> 205 Skip remote SMTP servers that greet with a 5XX sta- 206 tus code (go away, do not try again later). 207 208 <b><a href="postconf.5.html#smtp_skip_quit_response">smtp_skip_quit_response</a> (yes)</b> 209 Do not wait for the response to the SMTP QUIT com- 210 mand. 211 212 Available in Postfix version 2.0 and earlier: 213 214 <b><a href="postconf.5.html#smtp_skip_4xx_greeting">smtp_skip_4xx_greeting</a> (yes)</b> 215 Skip SMTP servers that greet with a 4XX status code 216 (go away, try again later). 217 218 Available in Postfix version 2.2 and later: 219 220 <b><a href="postconf.5.html#smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a> (empty)</b> 221 Lookup tables, indexed by the remote SMTP server 222 address, with case insensitive lists of EHLO key- 223 words (pipelining, starttls, auth, etc.) that the 224 Postfix SMTP client will ignore in the EHLO 225 response from a remote SMTP server. 226 227 <b><a href="postconf.5.html#smtp_discard_ehlo_keywords">smtp_discard_ehlo_keywords</a> (empty)</b> 228 A case insensitive list of EHLO keywords (pipelin- 229 ing, starttls, auth, etc.) that the Postfix SMTP 230 client will ignore in the EHLO response from a 231 remote SMTP server. 232 233 <b><a href="postconf.5.html#smtp_generic_maps">smtp_generic_maps</a> (empty)</b> 234 Optional lookup tables that perform address rewrit- 235 ing in the Postfix SMTP client, typically to trans- 236 form a locally valid address into a globally valid 237 address when sending mail across the Internet. 238 239 Available in Postfix version 2.2.9 and later: 240 241 <b><a href="postconf.5.html#smtp_cname_overrides_servername">smtp_cname_overrides_servername</a> (version dependent)</b> 242 Allow DNS CNAME records to override the servername 243 that the Postfix SMTP client uses for logging, SASL 244 password lookup, TLS policy decisions, or TLS cer- 245 tificate verification. 246 247 Available in Postfix version 2.3 and later: 248 249 <b><a href="postconf.5.html#lmtp_discard_lhlo_keyword_address_maps">lmtp_discard_lhlo_keyword_address_maps</a> (empty)</b> 250 Lookup tables, indexed by the remote LMTP server 251 address, with case insensitive lists of LHLO key- 252 words (pipelining, starttls, auth, etc.) that the 253 Postfix LMTP client will ignore in the LHLO 254 response from a remote LMTP server. 255 256 <b><a href="postconf.5.html#lmtp_discard_lhlo_keywords">lmtp_discard_lhlo_keywords</a> (empty)</b> 257 A case insensitive list of LHLO keywords (pipelin- 258 ing, starttls, auth, etc.) that the Postfix LMTP 259 client will ignore in the LHLO response from a 260 remote LMTP server. 261 262 Available in Postfix version 2.4.4 and later: 263 264 <b><a href="postconf.5.html#send_cyrus_sasl_authzid">send_cyrus_sasl_authzid</a> (no)</b> 265 When authenticating to a remote SMTP or LMTP server 266 with the default setting "no", send no SASL autho- 267 riZation ID (authzid); send only the SASL authenti- 268 Cation ID (authcid) plus the authcid's password. 269 270 Available in Postfix version 2.5 and later: 271 272 <b><a href="postconf.5.html#smtp_header_checks">smtp_header_checks</a> (empty)</b> 273 Restricted <a href="header_checks.5.html"><b>header_checks</b>(5)</a> tables for the Postfix 274 SMTP client. 275 276 <b><a href="postconf.5.html#smtp_mime_header_checks">smtp_mime_header_checks</a> (empty)</b> 277 Restricted <b><a href="postconf.5.html#mime_header_checks">mime_header_checks</a></b>(5) tables for the 278 Postfix SMTP client. 279 280 <b><a href="postconf.5.html#smtp_nested_header_checks">smtp_nested_header_checks</a> (empty)</b> 281 Restricted <b><a href="postconf.5.html#nested_header_checks">nested_header_checks</a></b>(5) tables for the 282 Postfix SMTP client. 283 284 <b><a href="postconf.5.html#smtp_body_checks">smtp_body_checks</a> (empty)</b> 285 Restricted <a href="header_checks.5.html"><b>body_checks</b>(5)</a> tables for the Postfix 286 SMTP client. 287 288 Available in Postfix version 2.6 and later: 289 290 <b><a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a> (0)</b> 291 An optional workaround for routers that break TCP 292 window scaling. 293 294 Available in Postfix version 2.8 and later: 295 296 <b><a href="postconf.5.html#smtp_dns_resolver_options">smtp_dns_resolver_options</a> (empty)</b> 297 DNS Resolver options for the Postfix SMTP client. 298 299 Available in Postfix version 2.9 and later: 300 301 <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b> 302 Change the behavior of the smtp_*_timeout time lim- 303 its, from a time limit per read or write system 304 call, to a time limit to send or receive a complete 305 record (an SMTP command line, SMTP response line, 306 SMTP message content line, or TLS protocol mes- 307 sage). 308 309 <b><a href="postconf.5.html#smtp_send_dummy_mail_auth">smtp_send_dummy_mail_auth</a> (no)</b> 310 Whether or not to append the "AUTH=<>" option to 311 the MAIL FROM command in SASL-authenticated SMTP 312 sessions. 313 314<b>MIME PROCESSING CONTROLS</b> 315 Available in Postfix version 2.0 and later: 316 317 <b><a href="postconf.5.html#disable_mime_output_conversion">disable_mime_output_conversion</a> (no)</b> 318 Disable the conversion of 8BITMIME format to 7BIT 319 format. 320 321 <b><a href="postconf.5.html#mime_boundary_length_limit">mime_boundary_length_limit</a> (2048)</b> 322 The maximal length of MIME multipart boundary 323 strings. 324 325 <b><a href="postconf.5.html#mime_nesting_limit">mime_nesting_limit</a> (100)</b> 326 The maximal recursion level that the MIME processor 327 will handle. 328 329<b>EXTERNAL CONTENT INSPECTION CONTROLS</b> 330 Available in Postfix version 2.1 and later: 331 332 <b><a href="postconf.5.html#smtp_send_xforward_command">smtp_send_xforward_command</a> (no)</b> 333 Send the non-standard XFORWARD command when the 334 Postfix SMTP server EHLO response announces XFOR- 335 WARD support. 336 337<b>SASL AUTHENTICATION CONTROLS</b> 338 <b><a href="postconf.5.html#smtp_sasl_auth_enable">smtp_sasl_auth_enable</a> (no)</b> 339 Enable SASL authentication in the Postfix SMTP 340 client. 341 342 <b><a href="postconf.5.html#smtp_sasl_password_maps">smtp_sasl_password_maps</a> (empty)</b> 343 Optional Postfix SMTP client lookup tables with one 344 username:password entry per remote hostname or 345 domain, or sender address when sender-dependent 346 authentication is enabled. 347 348 <b><a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a> (noplaintext, noanonymous)</b> 349 Postfix SMTP client SASL security options; as of 350 Postfix 2.3 the list of available features depends 351 on the SASL client implementation that is selected 352 with <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>. 353 354 Available in Postfix version 2.2 and later: 355 356 <b><a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> (empty)</b> 357 If non-empty, a Postfix SMTP client filter for the 358 remote SMTP server's list of offered SASL mecha- 359 nisms. 360 361 Available in Postfix version 2.3 and later: 362 363 <b><a href="postconf.5.html#smtp_sender_dependent_authentication">smtp_sender_dependent_authentication</a> (no)</b> 364 Enable sender-dependent authentication in the Post- 365 fix SMTP client; this is available only with SASL 366 authentication, and disables SMTP connection 367 caching to ensure that mail from different senders 368 will use the appropriate credentials. 369 370 <b><a href="postconf.5.html#smtp_sasl_path">smtp_sasl_path</a> (empty)</b> 371 Implementation-specific information that the Post- 372 fix SMTP client passes through to the SASL plug-in 373 implementation that is selected with 374 <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>. 375 376 <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a> (cyrus)</b> 377 The SASL plug-in type that the Postfix SMTP client 378 should use for authentication. 379 380 Available in Postfix version 2.5 and later: 381 382 <b><a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> (empty)</b> 383 An optional table to prevent repeated SASL authen- 384 tication failures with the same remote SMTP server 385 hostname, username and password. 386 387 <b><a href="postconf.5.html#smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a> (90d)</b> 388 The maximal age of an <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> 389 entry before it is removed. 390 391 <b><a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> (yes)</b> 392 When a remote SMTP server rejects a SASL authenti- 393 cation request with a 535 reply code, defer mail 394 delivery instead of returning mail as undeliver- 395 able. 396 397 Available in Postfix version 2.9 and later: 398 399 <b><a href="postconf.5.html#smtp_send_dummy_mail_auth">smtp_send_dummy_mail_auth</a> (no)</b> 400 Whether or not to append the "AUTH=<>" option to 401 the MAIL FROM command in SASL-authenticated SMTP 402 sessions. 403 404<b>STARTTLS SUPPORT CONTROLS</b> 405 Detailed information about STARTTLS configuration may be 406 found in the <a href="TLS_README.html">TLS_README</a> document. 407 408 <b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> (empty)</b> 409 The default SMTP TLS security level for the Postfix 410 SMTP client; when a non-empty value is specified, 411 this overrides the obsolete parameters 412 <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 413 <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a>. 414 415 <b><a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a> ($<a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_secu</a>-</b> 416 <b><a href="postconf.5.html#smtp_sasl_security_options">rity_options</a>)</b> 417 The SASL authentication security options that the 418 Postfix SMTP client uses for TLS encrypted SMTP 419 sessions. 420 421 <b><a href="postconf.5.html#smtp_starttls_timeout">smtp_starttls_timeout</a> (300s)</b> 422 Time limit for Postfix SMTP client write and read 423 operations during TLS startup and shutdown hand- 424 shake procedures. 425 426 <b><a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a> (empty)</b> 427 A file containing CA certificates of root CAs 428 trusted to sign either remote SMTP server certifi- 429 cates or intermediate CA certificates. 430 431 <b><a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> (empty)</b> 432 Directory with PEM format certificate authority 433 certificates that the Postfix SMTP client uses to 434 verify a remote SMTP server certificate. 435 436 <b><a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> (empty)</b> 437 File with the Postfix SMTP client RSA certificate 438 in PEM format. 439 440 <b><a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> (medium)</b> 441 The minimum TLS cipher grade that the Postfix SMTP 442 client will use with mandatory TLS encryption. 443 444 <b><a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> (empty)</b> 445 List of ciphers or cipher types to exclude from the 446 Postfix SMTP client cipher list at all TLS security 447 levels. 448 449 <b><a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> (empty)</b> 450 Additional list of ciphers or cipher types to 451 exclude from the Postfix SMTP client cipher list at 452 mandatory TLS security levels. 453 454 <b><a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> (empty)</b> 455 File with the Postfix SMTP client DSA certificate 456 in PEM format. 457 458 <b><a href="postconf.5.html#smtp_tls_dkey_file">smtp_tls_dkey_file</a> ($<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a>)</b> 459 File with the Postfix SMTP client DSA private key 460 in PEM format. 461 462 <b><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>)</b> 463 File with the Postfix SMTP client RSA private key 464 in PEM format. 465 466 <b><a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> (0)</b> 467 Enable additional Postfix SMTP client logging of 468 TLS activity. 469 470 <b><a href="postconf.5.html#smtp_tls_note_starttls_offer">smtp_tls_note_starttls_offer</a> (no)</b> 471 Log the hostname of a remote SMTP server that 472 offers STARTTLS, when TLS is not already enabled 473 for that server. 474 475 <b><a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> (empty)</b> 476 Optional lookup tables with the Postfix SMTP client 477 TLS security policy by next-hop destination; when a 478 non-empty value is specified, this overrides the 479 obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter. 480 481 <b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (!SSLv2)</b> 482 List of SSL/TLS protocols that the Postfix SMTP 483 client will use with mandatory TLS encryption. 484 485 <b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b> 486 The verification depth for remote SMTP server cer- 487 tificates. 488 489 <b><a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> (nexthop, dot-nexthop)</b> 490 How the Postfix SMTP client verifies the server 491 certificate peername for the "secure" TLS security 492 level. 493 494 <b><a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> (empty)</b> 495 Name of the file containing the optional Postfix 496 SMTP client TLS session cache. 497 498 <b><a href="postconf.5.html#smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> (3600s)</b> 499 The expiration time of Postfix SMTP client TLS ses- 500 sion cache information. 501 502 <b><a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> (hostname)</b> 503 How the Postfix SMTP client verifies the server 504 certificate peername for the "verify" TLS security 505 level. 506 507 <b><a href="postconf.5.html#tls_daemon_random_bytes">tls_daemon_random_bytes</a> (32)</b> 508 The number of pseudo-random bytes that an <a href="smtp.8.html"><b>smtp</b>(8)</a> 509 or <a href="smtpd.8.html"><b>smtpd</b>(8)</a> process requests from the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> 510 server in order to seed its internal pseudo random 511 number generator (PRNG). 512 513 <b><a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a></b> 514 <b>(ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)</b> 515 The OpenSSL cipherlist for "HIGH" grade ciphers. 516 517 <b><a href="postconf.5.html#tls_medium_cipherlist">tls_medium_cipherlist</a> (ALL:!EXPORT:!LOW:+RC4:@STRENGTH)</b> 518 The OpenSSL cipherlist for "MEDIUM" or higher grade 519 ciphers. 520 521 <b><a href="postconf.5.html#tls_low_cipherlist">tls_low_cipherlist</a> (ALL:!EXPORT:+RC4:@STRENGTH)</b> 522 The OpenSSL cipherlist for "LOW" or higher grade 523 ciphers. 524 525 <b><a href="postconf.5.html#tls_export_cipherlist">tls_export_cipherlist</a> (ALL:+RC4:@STRENGTH)</b> 526 The OpenSSL cipherlist for "EXPORT" or higher grade 527 ciphers. 528 529 <b><a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> (eNULL:!aNULL)</b> 530 The OpenSSL cipherlist for "NULL" grade ciphers 531 that provide authentication without encryption. 532 533 Available in Postfix version 2.4 and later: 534 535 <b><a href="postconf.5.html#smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a></b> 536 <b>($<a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a>)</b> 537 The SASL authentication security options that the 538 Postfix SMTP client uses for TLS encrypted SMTP 539 sessions with a verified server certificate. 540 541 Available in Postfix version 2.5 and later: 542 543 <b><a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> (empty)</b> 544 List of acceptable remote SMTP server certificate 545 fingerprints for the "fingerprint" TLS security 546 level (<b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a></b> = fingerprint). 547 548 <b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> (md5)</b> 549 The message digest algorithm used to construct 550 remote SMTP server certificate fingerprints. 551 552 Available in Postfix version 2.6 and later: 553 554 <b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (!SSLv2)</b> 555 List of TLS protocols that the Postfix SMTP client 556 will exclude or include with opportunistic TLS 557 encryption. 558 559 <b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (export)</b> 560 The minimum TLS cipher grade that the Postfix SMTP 561 client will use with opportunistic TLS encryption. 562 563 <b><a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> (empty)</b> 564 File with the Postfix SMTP client ECDSA certificate 565 in PEM format. 566 567 <b><a href="postconf.5.html#smtp_tls_eckey_file">smtp_tls_eckey_file</a> ($<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>)</b> 568 File with the Postfix SMTP client ECDSA private key 569 in PEM format. 570 571 Available in Postfix version 2.7 and later: 572 573 <b><a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> (no)</b> 574 Try to detect a mail hijacking attack based on a 575 TLS protocol vulnerability (CVE-2009-3555), where 576 an attacker prepends malicious HELO, MAIL, RCPT, 577 DATA commands to a Postfix SMTP client TLS session. 578 579 Available in Postfix version 2.8 and later: 580 581 <b><a href="postconf.5.html#tls_disable_workarounds">tls_disable_workarounds</a> (see 'postconf -d' output)</b> 582 List or bit-mask of OpenSSL bug work-arounds to 583 disable. 584 585<b>OBSOLETE STARTTLS CONTROLS</b> 586 The following configuration parameters exist for compati- 587 bility with Postfix versions before 2.3. Support for these 588 will be removed in a future release. 589 590 <b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b> 591 Opportunistic mode: use TLS when a remote SMTP 592 server announces STARTTLS support, otherwise send 593 the mail in the clear. 594 595 <b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b> 596 Enforcement mode: require that remote SMTP servers 597 use TLS encryption, and never send mail in the 598 clear. 599 600 <b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b> 601 With mandatory TLS encryption, require that the 602 remote SMTP server hostname matches the information 603 in the remote SMTP server certificate. 604 605 <b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b> 606 Optional lookup tables with the Postfix SMTP client 607 TLS usage policy by next-hop destination and by 608 remote SMTP server hostname. 609 610 <b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b> 611 Obsolete Postfix < 2.3 control for the Postfix SMTP 612 client TLS cipher list. 613 614<b>RESOURCE AND RATE CONTROLS</b> 615 <b><a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b> 616 <b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_limit</a>)</b> 617 The maximal number of parallel deliveries to the 618 same destination via the smtp message delivery 619 transport. 620 621 <b><a href="postconf.5.html#smtp_destination_recipient_limit">smtp_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b> 622 <b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b> 623 The maximal number of recipients per message for 624 the smtp message delivery transport. 625 626 <b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b> 627 The Postfix SMTP client time limit for completing a 628 TCP connection, or zero (use the operating system 629 built-in time limit). 630 631 <b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b> 632 The Postfix SMTP client time limit for sending the 633 HELO or EHLO command, and for receiving the initial 634 remote SMTP server response. 635 636 <b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b> 637 The Postfix LMTP client time limit for sending the 638 LHLO command, and for receiving the initial remote 639 LMTP server response. 640 641 <b><a href="postconf.5.html#smtp_xforward_timeout">smtp_xforward_timeout</a> (300s)</b> 642 The Postfix SMTP client time limit for sending the 643 XFORWARD command, and for receiving the remote SMTP 644 server response. 645 646 <b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b> 647 The Postfix SMTP client time limit for sending the 648 MAIL FROM command, and for receiving the remote 649 SMTP server response. 650 651 <b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b> 652 The Postfix SMTP client time limit for sending the 653 SMTP RCPT TO command, and for receiving the remote 654 SMTP server response. 655 656 <b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b> 657 The Postfix SMTP client time limit for sending the 658 SMTP DATA command, and for receiving the remote 659 SMTP server response. 660 661 <b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b> 662 The Postfix SMTP client time limit for sending the 663 SMTP message content. 664 665 <b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b> 666 The Postfix SMTP client time limit for sending the 667 SMTP ".", and for receiving the remote SMTP server 668 response. 669 670 <b><a href="postconf.5.html#smtp_quit_timeout">smtp_quit_timeout</a> (300s)</b> 671 The Postfix SMTP client time limit for sending the 672 QUIT command, and for receiving the remote SMTP 673 server response. 674 675 Available in Postfix version 2.1 and later: 676 677 <b><a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> (5)</b> 678 The maximal number of MX (mail exchanger) IP 679 addresses that can result from Postfix SMTP client 680 mail exchanger lookups, or zero (no limit). 681 682 <b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b> 683 The maximal number of SMTP sessions per delivery 684 request before the Postfix SMTP client gives up or 685 delivers to a fall-back <a href="postconf.5.html#relayhost">relay host</a>, or zero (no 686 limit). 687 688 <b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b> 689 The Postfix SMTP client time limit for sending the 690 RSET command, and for receiving the remote SMTP 691 server response. 692 693 Available in Postfix version 2.2 and earlier: 694 695 <b><a href="postconf.5.html#lmtp_cache_connection">lmtp_cache_connection</a> (yes)</b> 696 Keep Postfix LMTP client connections open for up to 697 $<a href="postconf.5.html#max_idle">max_idle</a> seconds. 698 699 Available in Postfix version 2.2 and later: 700 701 <b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b> 702 Permanently enable SMTP connection caching for the 703 specified destinations. 704 705 <b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b> 706 Temporarily enable SMTP connection caching while a 707 destination has a high volume of mail in the active 708 queue. 709 710 <b><a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> (300s)</b> 711 The amount of time during which Postfix will use an 712 SMTP connection repeatedly. 713 714 <b><a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> (2s)</b> 715 When SMTP connection caching is enabled, the amount 716 of time that an unused SMTP client socket is kept 717 open before it is closed. 718 719 Available in Postfix version 2.3 and later: 720 721 <b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b> 722 Time limit for connection cache connect, send or 723 receive operations. 724 725 Available in Postfix version 2.9 and later: 726 727 <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b> 728 Change the behavior of the smtp_*_timeout time lim- 729 its, from a time limit per read or write system 730 call, to a time limit to send or receive a complete 731 record (an SMTP command line, SMTP response line, 732 SMTP message content line, or TLS protocol mes- 733 sage). 734 735<b>TROUBLE SHOOTING CONTROLS</b> 736 <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b> 737 The increment in verbose logging level when a 738 remote client or server matches a pattern in the 739 <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter. 740 741 <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b> 742 Optional list of remote client or server hostname 743 or network address patterns that cause the verbose 744 logging level to increase by the amount specified 745 in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>. 746 747 <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b> 748 The recipient of postmaster notifications about 749 mail delivery problems that are caused by policy, 750 resource, software or protocol errors. 751 752 <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b> 753 What categories of Postfix-generated mail are sub- 754 ject to before-queue content inspection by 755 <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>, <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>. 756 757 <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b> 758 The list of error classes that are reported to the 759 postmaster. 760 761<b>MISCELLANEOUS CONTROLS</b> 762 <b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b> 763 Where the Postfix SMTP client should deliver mail 764 when it detects a "mail loops back to myself" error 765 condition. 766 767 <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b> 768 The default location of the Postfix <a href="postconf.5.html">main.cf</a> and 769 <a href="master.5.html">master.cf</a> configuration files. 770 771 <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b> 772 How much time a Postfix daemon process may take to 773 handle a request before it is terminated by a 774 built-in watchdog timer. 775 776 <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b> 777 The maximal number of digits after the decimal 778 point when logging sub-second delay values. 779 780 <b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b> 781 Disable DNS lookups in the Postfix SMTP and LMTP 782 clients. 783 784 <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b> 785 The network interface addresses that this mail sys- 786 tem receives mail on. 787 788 <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (all)</b> 789 The Internet protocols Postfix will attempt to use 790 when making or accepting connections. 791 792 <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b> 793 The time limit for sending or receiving information 794 over an internal communication channel. 795 796 <b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b> 797 When a remote LMTP server announces no DSN support, 798 assume that the server performs final delivery, and 799 send "delivered" delivery status notifications 800 instead of "relayed". 801 802 <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b> 803 The default TCP port that the Postfix LMTP client 804 connects to. 805 806 <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b> 807 The maximum amount of time that an idle Postfix 808 daemon process waits for an incoming connection 809 before terminating voluntarily. 810 811 <b><a href="postconf.5.html#max_use">max_use</a> (100)</b> 812 The maximal number of incoming connections that a 813 Postfix daemon process will service before termi- 814 nating voluntarily. 815 816 <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b> 817 The process ID of a Postfix command or daemon 818 process. 819 820 <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b> 821 The process name of a Postfix command or daemon 822 process. 823 824 <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b> 825 The network interface addresses that this mail sys- 826 tem receives mail on by way of a proxy or network 827 address translation unit. 828 829 <b><a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> (any)</b> 830 The address type ("ipv6", "ipv4" or "any") that the 831 Postfix SMTP client will try first, when a destina- 832 tion has IPv6 and IPv4 addresses with equal MX 833 preference. 834 835 <b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b> 836 An optional numerical network address that the 837 Postfix SMTP client should bind to when making an 838 IPv4 connection. 839 840 <b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b> 841 An optional numerical network address that the 842 Postfix SMTP client should bind to when making an 843 IPv6 connection. 844 845 <b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b> 846 The hostname to send in the SMTP EHLO or HELO com- 847 mand. 848 849 <b><a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b> 850 The hostname to send in the LMTP LHLO command. 851 852 <b><a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> (dns)</b> 853 What mechanisms the Postfix SMTP client uses to 854 look up a host's IP address. 855 856 <b><a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> (yes)</b> 857 Randomize the order of equal-preference MX host 858 addresses. 859 860 <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b> 861 The syslog facility of Postfix logging. 862 863 <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b> 864 The mail system name that is prepended to the 865 process name in syslog records, so that "smtpd" 866 becomes, for example, "postfix/smtpd". 867 868 Available with Postfix 2.2 and earlier: 869 870 <b><a href="postconf.5.html#fallback_relay">fallback_relay</a> (empty)</b> 871 Optional list of relay hosts for SMTP destinations 872 that can't be found or that are unreachable. 873 874 Available with Postfix 2.3 and later: 875 876 <b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b> 877 Optional list of relay hosts for SMTP destinations 878 that can't be found or that are unreachable. 879 880<b>SEE ALSO</b> 881 <a href="generic.5.html">generic(5)</a>, output address rewriting 882 <a href="header_checks.5.html">header_checks(5)</a>, message header content inspection 883 <a href="header_checks.5.html">body_checks(5)</a>, body parts content inspection 884 <a href="qmgr.8.html">qmgr(8)</a>, queue manager 885 <a href="bounce.8.html">bounce(8)</a>, delivery status reports 886 <a href="scache.8.html">scache(8)</a>, connection cache server 887 <a href="postconf.5.html">postconf(5)</a>, configuration parameters 888 <a href="master.5.html">master(5)</a>, generic daemon options 889 <a href="master.8.html">master(8)</a>, process manager 890 <a href="tlsmgr.8.html">tlsmgr(8)</a>, TLS session and PRNG management 891 syslogd(8), system logging 892 893<b>README FILES</b> 894 <a href="SASL_README.html">SASL_README</a>, Postfix SASL howto 895 <a href="TLS_README.html">TLS_README</a>, Postfix STARTTLS howto 896 897<b>LICENSE</b> 898 The Secure Mailer license must be distributed with this 899 software. 900 901<b>AUTHOR(S)</b> 902 Wietse Venema 903 IBM T.J. Watson Research 904 P.O. Box 704 905 Yorktown Heights, NY 10598, USA 906 907 Command pipelining in cooperation with: 908 Jon Ribbens 909 Oaktree Internet Solutions Ltd., 910 Internet House, 911 Canal Basin, 912 Coventry, 913 CV1 4LY, United Kingdom. 914 915 SASL support originally by: 916 Till Franke 917 SuSE Rhein/Main AG 918 65760 Eschborn, Germany 919 920 TLS support originally by: 921 Lutz Jaenicke 922 BTU Cottbus 923 Allgemeine Elektrotechnik 924 Universitaetsplatz 3-4 925 D-03044 Cottbus, Germany 926 927 Revised TLS and SMTP connection cache support by: 928 Victor Duchovni 929 Morgan Stanley 930 931 SMTP(8) 932</pre> </body> </html> 933