1# ACCESS(5) ACCESS(5) 2# 3# NAME 4# access - Postfix SMTP server access table 5# 6# SYNOPSIS 7# postmap /etc/postfix/access 8# 9# postmap -q "string" /etc/postfix/access 10# 11# postmap -q - /etc/postfix/access <inputfile 12# 13# DESCRIPTION 14# This document describes access control on remote SMTP 15# client information: host names, network addresses, and 16# envelope sender or recipient addresses; it is implemented 17# by the Postfix SMTP server. See header_checks(5) or 18# body_checks(5) for access control on the content of email 19# messages. 20# 21# Normally, the access(5) table is specified as a text file 22# that serves as input to the postmap(1) command. The 23# result, an indexed file in dbm or db format, is used for 24# fast searching by the mail system. Execute the command 25# "postmap /etc/postfix/access" to rebuild an indexed file 26# after changing the corresponding text file. 27# 28# When the table is provided via other means such as NIS, 29# LDAP or SQL, the same lookups are done as for ordinary 30# indexed files. 31# 32# Alternatively, the table can be provided as a regular- 33# expression map where patterns are given as regular expres- 34# sions, or lookups can be directed to TCP-based server. In 35# those cases, the lookups are done in a slightly different 36# way as described below under "REGULAR EXPRESSION TABLES" 37# or "TCP-BASED TABLES". 38# 39# CASE FOLDING 40# The search string is folded to lowercase before database 41# lookup. As of Postfix 2.3, the search string is not case 42# folded with database types such as regexp: or pcre: whose 43# lookup fields can match both upper and lower case. 44# 45# TABLE FORMAT 46# The input format for the postmap(1) command is as follows: 47# 48# pattern action 49# When pattern matches a mail address, domain or host 50# address, perform the corresponding action. 51# 52# blank lines and comments 53# Empty lines and whitespace-only lines are ignored, 54# as are lines whose first non-whitespace character 55# is a `#'. 56# 57# multi-line text 58# A logical line starts with non-whitespace text. A 59# line that starts with whitespace continues a logi- 60# cal line. 61# 62# EMAIL ADDRESS PATTERNS 63# With lookups from indexed files such as DB or DBM, or from 64# networked tables such as NIS, LDAP or SQL, patterns are 65# tried in the order as listed below: 66# 67# user@domain 68# Matches the specified mail address. 69# 70# domain.tld 71# Matches domain.tld as the domain part of an email 72# address. 73# 74# The pattern domain.tld also matches subdomains, but 75# only when the string smtpd_access_maps is listed in 76# the Postfix parent_domain_matches_subdomains con- 77# figuration setting. 78# 79# .domain.tld 80# Matches subdomains of domain.tld, but only when the 81# string smtpd_access_maps is not listed in the Post- 82# fix parent_domain_matches_subdomains configuration 83# setting. 84# 85# user@ Matches all mail addresses with the specified user 86# part. 87# 88# Note: lookup of the null sender address is not possible 89# with some types of lookup table. By default, Postfix uses 90# <> as the lookup key for such addresses. The value is 91# specified with the smtpd_null_access_lookup_key parameter 92# in the Postfix main.cf file. 93# 94# EMAIL ADDRESS EXTENSION 95# When a mail address localpart contains the optional recip- 96# ient delimiter (e.g., user+foo@domain), the lookup order 97# becomes: user+foo@domain, user@domain, domain, user+foo@, 98# and user@. 99# 100# HOST NAME/ADDRESS PATTERNS 101# With lookups from indexed files such as DB or DBM, or from 102# networked tables such as NIS, LDAP or SQL, the following 103# lookup patterns are examined in the order as listed: 104# 105# domain.tld 106# Matches domain.tld. 107# 108# The pattern domain.tld also matches subdomains, but 109# only when the string smtpd_access_maps is listed in 110# the Postfix parent_domain_matches_subdomains con- 111# figuration setting. 112# 113# .domain.tld 114# Matches subdomains of domain.tld, but only when the 115# string smtpd_access_maps is not listed in the Post- 116# fix parent_domain_matches_subdomains configuration 117# setting. 118# 119# net.work.addr.ess 120# 121# net.work.addr 122# 123# net.work 124# 125# net Matches the specified IPv4 host address or subnet- 126# work. An IPv4 host address is a sequence of four 127# decimal octets separated by ".". 128# 129# Subnetworks are matched by repeatedly truncating 130# the last ".octet" from the remote IPv4 host address 131# string until a match is found in the access table, 132# or until further truncation is not possible. 133# 134# NOTE 1: The access map lookup key must be in canon- 135# ical form: do not specify unnecessary null charac- 136# ters, and do not enclose network address informa- 137# tion with "[]" characters. 138# 139# NOTE 2: use the cidr lookup table type to specify 140# network/netmask patterns. See cidr_table(5) for 141# details. 142# 143# net:work:addr:ess 144# 145# net:work:addr 146# 147# net:work 148# 149# net Matches the specified IPv6 host address or subnet- 150# work. An IPv6 host address is a sequence of three 151# to eight hexadecimal octet pairs separated by ":". 152# 153# Subnetworks are matched by repeatedly truncating 154# the last ":octetpair" from the remote IPv6 host 155# address string until a match is found in the access 156# table, or until further truncation is not possible. 157# 158# NOTE 1: the truncation and comparison are done with 159# the string representation of the IPv6 host address. 160# Thus, not all the ":" subnetworks will be tried. 161# 162# NOTE 2: The access map lookup key must be in canon- 163# ical form: do not specify unnecessary null charac- 164# ters, and do not enclose network address informa- 165# tion with "[]" characters. 166# 167# NOTE 3: use the cidr lookup table type to specify 168# network/netmask patterns. See cidr_table(5) for 169# details. 170# 171# IPv6 support is available in Postfix 2.2 and later. 172# 173# ACCEPT ACTIONS 174# OK Accept the address etc. that matches the pattern. 175# 176# all-numerical 177# An all-numerical result is treated as OK. This for- 178# mat is generated by address-based relay authoriza- 179# tion schemes such as pop-before-smtp. 180# 181# For other accept actions, see "OTHER ACTIONS" below. 182# 183# REJECT ACTIONS 184# Postfix version 2.3 and later support enhanced status 185# codes as defined in RFC 3463. When no code is specified 186# at the beginning of the text below, Postfix inserts a 187# default enhanced status code of "5.7.1" in the case of 188# reject actions, and "4.7.1" in the case of defer actions. 189# See "ENHANCED STATUS CODES" below. 190# 191# 4NN text 192# 193# 5NN text 194# Reject the address etc. that matches the pattern, 195# and respond with the numerical three-digit code and 196# text. 4NN means "try again later", while 5NN means 197# "do not try again". 198# 199# The following responses have special meaning for 200# the Postfix SMTP server: 201# 202# 421 text (Postfix 2.3 and later) 203# 204# 521 text (Postfix 2.6 and later) 205# After responding with the numerical three- 206# digit code and text, disconnect immediately 207# from the SMTP client. This frees up SMTP 208# server resources so that they can be made 209# available to another SMTP client. 210# 211# Note: The "521" response should be used only 212# with botnets and other malware where inter- 213# operability is of no concern. The "send 521 214# and disconnect" behavior is NOT defined in 215# the SMTP standard. 216# 217# REJECT optional text... 218# Reject the address etc. that matches the pattern. 219# Reply with "$access_map_reject_code optional 220# text..." when the optional text is specified, oth- 221# erwise reply with a generic error response message. 222# 223# DEFER optional text... 224# Reject the address etc. that matches the pattern. 225# Reply with "$access_map_defer_code optional 226# text..." when the optional text is specified, oth- 227# erwise reply with a generic error response message. 228# 229# This feature is available in Postfix 2.6 and later. 230# 231# DEFER_IF_REJECT optional text... 232# Defer the request if some later restriction would 233# result in a REJECT action. Reply with 234# "$access_map_defer_code 4.7.1 optional text..." 235# when the optional text is specified, otherwise 236# reply with a generic error response message. 237# 238# Prior to Postfix 2.6, the SMTP reply code is 450. 239# 240# This feature is available in Postfix 2.1 and later. 241# 242# DEFER_IF_PERMIT optional text... 243# Defer the request if some later restriction would 244# result in a an explicit or implicit PERMIT action. 245# Reply with "$access_map_defer_code 4.7.1 optional 246# text..." when the optional text is specified, oth- 247# erwise reply with a generic error response message. 248# 249# Prior to Postfix 2.6, the SMTP reply code is 450. 250# 251# This feature is available in Postfix 2.1 and later. 252# 253# For other reject actions, see "OTHER ACTIONS" below. 254# 255# OTHER ACTIONS 256# restriction... 257# Apply the named UCE restriction(s) (permit, reject, 258# reject_unauth_destination, and so on). 259# 260# BCC user@domain 261# Send one copy of the message to the specified 262# recipient. 263# 264# If multiple BCC actions are specified within the 265# same SMTP MAIL transaction, only the last action 266# will be used. 267# 268# This feature is not part of the stable Postfix 269# release. 270# 271# DISCARD optional text... 272# Claim successful delivery and silently discard the 273# message. Log the optional text if specified, oth- 274# erwise log a generic message. 275# 276# Note: this action currently affects all recipients 277# of the message. To discard only one recipient 278# without discarding the entire message, use the 279# transport(5) table to direct mail to the discard(8) 280# service. 281# 282# This feature is available in Postfix 2.0 and later. 283# 284# DUNNO Pretend that the lookup key was not found. This 285# prevents Postfix from trying substrings of the 286# lookup key (such as a subdomain name, or a network 287# address subnetwork). 288# 289# This feature is available in Postfix 2.0 and later. 290# 291# FILTER transport:destination 292# After the message is queued, send the entire mes- 293# sage through the specified external content filter. 294# The transport name specifies the first field of a 295# mail delivery agent definition in master.cf; the 296# syntax of the next-hop destination is described in 297# the manual page of the corresponding delivery 298# agent. More information about external content 299# filters is in the Postfix FILTER_README file. 300# 301# Note 1: do not use $number regular expression sub- 302# stitutions for transport or destination unless you 303# know that the information has a trusted origin. 304# 305# Note 2: this action overrides the main.cf con- 306# tent_filter setting, and affects all recipients of 307# the message. In the case that multiple FILTER 308# actions fire, only the last one is executed. 309# 310# Note 3: the purpose of the FILTER command is to 311# override message routing. To override the recipi- 312# ent's transport but not the next-hop destination, 313# specify an empty filter destination (Postfix 2.7 314# and later), or specify a transport:destination that 315# delivers through a different Postfix instance 316# (Postfix 2.6 and earlier). Other options are using 317# the recipient-dependent transport_maps or the sen- 318# der-dependent sender_dependent_default_transport- 319# _maps features. 320# 321# This feature is available in Postfix 2.0 and later. 322# 323# HOLD optional text... 324# Place the message on the hold queue, where it will 325# sit until someone either deletes it or releases it 326# for delivery. Log the optional text if specified, 327# otherwise log a generic message. 328# 329# Mail that is placed on hold can be examined with 330# the postcat(1) command, and can be destroyed or 331# released with the postsuper(1) command. 332# 333# Note: use "postsuper -r" to release mail that was 334# kept on hold for a significant fraction of $maxi- 335# mal_queue_lifetime or $bounce_queue_lifetime, or 336# longer. Use "postsuper -H" only for mail that will 337# not expire within a few delivery attempts. 338# 339# Note: this action currently affects all recipients 340# of the message. 341# 342# This feature is available in Postfix 2.0 and later. 343# 344# PREPEND headername: headervalue 345# Prepend the specified message header to the mes- 346# sage. When more than one PREPEND action executes, 347# the first prepended header appears before the sec- 348# ond etc. prepended header. 349# 350# Note: this action must execute before the message 351# content is received; it cannot execute in the con- 352# text of smtpd_end_of_data_restrictions. 353# 354# This feature is available in Postfix 2.1 and later. 355# 356# REDIRECT user@domain 357# After the message is queued, send the message to 358# the specified address instead of the intended 359# recipient(s). 360# 361# Note: this action overrides the FILTER action, and 362# currently affects all recipients of the message. 363# 364# This feature is available in Postfix 2.1 and later. 365# 366# WARN optional text... 367# Log a warning with the optional text, together with 368# client information and if available, with helo, 369# sender, recipient and protocol information. 370# 371# This feature is available in Postfix 2.1 and later. 372# 373# ENHANCED STATUS CODES 374# Postfix version 2.3 and later support enhanced status 375# codes as defined in RFC 3463. When an enhanced status 376# code is specified in an access table, it is subject to 377# modification. The following transformations are needed 378# when the same access table is used for client, helo, 379# sender, or recipient access restrictions; they happen 380# regardless of whether Postfix replies to a MAIL FROM, RCPT 381# TO or other SMTP command. 382# 383# o When a sender address matches a REJECT action, the 384# Postfix SMTP server will transform a recipient DSN 385# status (e.g., 4.1.1-4.1.6) into the corresponding 386# sender DSN status, and vice versa. 387# 388# o When non-address information matches a REJECT 389# action (such as the HELO command argument or the 390# client hostname/address), the Postfix SMTP server 391# will transform a sender or recipient DSN status 392# into a generic non-address DSN status (e.g., 393# 4.0.0). 394# 395# REGULAR EXPRESSION TABLES 396# This section describes how the table lookups change when 397# the table is given in the form of regular expressions. For 398# a description of regular expression lookup table syntax, 399# see regexp_table(5) or pcre_table(5). 400# 401# Each pattern is a regular expression that is applied to 402# the entire string being looked up. Depending on the appli- 403# cation, that string is an entire client hostname, an 404# entire client IP address, or an entire mail address. Thus, 405# no parent domain or parent network search is done, 406# user@domain mail addresses are not broken up into their 407# user@ and domain constituent parts, nor is user+foo broken 408# up into user and foo. 409# 410# Patterns are applied in the order as specified in the ta- 411# ble, until a pattern is found that matches the search 412# string. 413# 414# Actions are the same as with indexed file lookups, with 415# the additional feature that parenthesized substrings from 416# the pattern can be interpolated as $1, $2 and so on. 417# 418# TCP-BASED TABLES 419# This section describes how the table lookups change when 420# lookups are directed to a TCP-based server. For a descrip- 421# tion of the TCP client/server lookup protocol, see tcp_ta- 422# ble(5). This feature is not available up to and including 423# Postfix version 2.4. 424# 425# Each lookup operation uses the entire query string once. 426# Depending on the application, that string is an entire 427# client hostname, an entire client IP address, or an entire 428# mail address. Thus, no parent domain or parent network 429# search is done, user@domain mail addresses are not broken 430# up into their user@ and domain constituent parts, nor is 431# user+foo broken up into user and foo. 432# 433# Actions are the same as with indexed file lookups. 434# 435# EXAMPLE 436# The following example uses an indexed file, so that the 437# order of table entries does not matter. The example per- 438# mits access by the client at address 1.2.3.4 but rejects 439# all other clients in 1.2.3.0/24. Instead of hash lookup 440# tables, some systems use dbm. Use the command "postconf 441# -m" to find out what lookup tables Postfix supports on 442# your system. 443# 444# /etc/postfix/main.cf: 445# smtpd_client_restrictions = 446# check_client_access hash:/etc/postfix/access 447# 448# /etc/postfix/access: 449# 1.2.3 REJECT 450# 1.2.3.4 OK 451# 452# Execute the command "postmap /etc/postfix/access" after 453# editing the file. 454# 455# BUGS 456# The table format does not understand quoting conventions. 457# 458# SEE ALSO 459# postmap(1), Postfix lookup table manager 460# smtpd(8), SMTP server 461# postconf(5), configuration parameters 462# transport(5), transport:nexthop syntax 463# 464# README FILES 465# Use "postconf readme_directory" or "postconf html_direc- 466# tory" to locate this information. 467# SMTPD_ACCESS_README, built-in SMTP server access control 468# DATABASE_README, Postfix lookup table overview 469# 470# LICENSE 471# The Secure Mailer license must be distributed with this 472# software. 473# 474# AUTHOR(S) 475# Wietse Venema 476# IBM T.J. Watson Research 477# P.O. Box 704 478# Yorktown Heights, NY 10598, USA 479# 480# ACCESS(5) 481