This is the default example configuration of access provided by Postfix. This config file was generated by Postfix running on RHEL 8.
It is located under: /etc/postfix/access
# ACCESS(5) ACCESS(5)
#
# NAME
# access - Postfix SMTP server access table
#
# SYNOPSIS
# postmap /etc/postfix/access
#
# postmap -q "string" /etc/postfix/access
#
# postmap -q - /etc/postfix/access <inputfile
#
# DESCRIPTION
# This document describes access control on remote SMTP
# client information: host names, network addresses, and
# envelope sender or recipient addresses; it is implemented
# by the Postfix SMTP server. See header_checks(5) or
# body_checks(5) for access control on the content of email
# messages.
#
# Normally, the access(5) table is specified as a text file
# that serves as input to the postmap(1) command. The
# result, an indexed file in dbm or db format, is used for
# fast searching by the mail system. Execute the command
# "postmap /etc/postfix/access" to rebuild an indexed file
# after changing the corresponding text file.
#
# When the table is provided via other means such as NIS,
# LDAP or SQL, the same lookups are done as for ordinary
# indexed files.
#
# Alternatively, the table can be provided as a regu-
# lar-expression map where patterns are given as regular
# expressions, or lookups can be directed to TCP-based
# server. In those cases, the lookups are done in a slightly
# different way as described below under "REGULAR EXPRESSION
# TABLES" or "TCP-BASED TABLES".
#
# CASE FOLDING
# The search string is folded to lowercase before database
# lookup. As of Postfix 2.3, the search string is not case
# folded with database types such as regexp: or pcre: whose
# lookup fields can match both upper and lower case.
#
# TABLE FORMAT
# The input format for the postmap(1) command is as follows:
#
# pattern action
# When pattern matches a mail address, domain or host
# address, perform the corresponding action.
#
# blank lines and comments
# Empty lines and whitespace-only lines are ignored,
# as are lines whose first non-whitespace character
# is a `#'.
#
# multi-line text
# A logical line starts with non-whitespace text. A
# line that starts with whitespace continues a logi-
# cal line.
#
# EMAIL ADDRESS PATTERNS
# With lookups from indexed files such as DB or DBM, or from
# networked tables such as NIS, LDAP or SQL, patterns are
# tried in the order as listed below:
#
# user@domain
# Matches the specified mail address.
#
# domain.tld
# Matches domain.tld as the domain part of an email
# address.
#
# The pattern domain.tld also matches subdomains, but
# only when the string smtpd_access_maps is listed in
# the Postfix parent_domain_matches_subdomains con-
# figuration setting.
#
# .domain.tld
# Matches subdomains of domain.tld, but only when the
# string smtpd_access_maps is not listed in the Post-
# fix parent_domain_matches_subdomains configuration
# setting.
#
# user@ Matches all mail addresses with the specified user
# part.
#
# Note: lookup of the null sender address is not possible
# with some types of lookup table. By default, Postfix uses
# <> as the lookup key for such addresses. The value is
# specified with the smtpd_null_access_lookup_key parameter
# in the Postfix main.cf file.
#
# EMAIL ADDRESS EXTENSION
# When a mail address localpart contains the optional recip-
# ient delimiter (e.g., user+foo@domain), the lookup order
# becomes: user+foo@domain, user@domain, domain, user+foo@,
# and user@.
#
# HOST NAME/ADDRESS PATTERNS
# With lookups from indexed files such as DB or DBM, or from
# networked tables such as NIS, LDAP or SQL, the following
# lookup patterns are examined in the order as listed:
#
# domain.tld
# Matches domain.tld.
#
# The pattern domain.tld also matches subdomains, but
# only when the string smtpd_access_maps is listed in
# the Postfix parent_domain_matches_subdomains con-
# figuration setting.
#
# .domain.tld
# Matches subdomains of domain.tld, but only when the
# string smtpd_access_maps is not listed in the Post-
# fix parent_domain_matches_subdomains configuration
# setting.
#
# net.work.addr.ess
#
# net.work.addr
#
# net.work
#
# net Matches a remote IPv4 host address or network
# address range. Specify one to four decimal octets
# separated by ".". Do not specify "[]" , "/", lead-
# ing zeros, or hexadecimal forms.
#
# Network ranges are matched by repeatedly truncating
# the last ".octet" from a remote IPv4 host address
# string, until a match is found in the access table,
# or until further truncation is not possible.
#
# NOTE: use the cidr lookup table type to specify
# network/netmask patterns. See cidr_table(5) for
# details.
#
# net:work:addr:ess
#
# net:work:addr
#
# net:work
#
# net Matches a remote IPv6 host address or network
# address range. Specify three to eight hexadecimal
# octet pairs separated by ":", using the compressed
# form "::" for a sequence of zero-valued octet
# pairs. Do not specify "[]", "/", leading zeros, or
# non-compressed forms.
#
# A network range is matched by repeatedly truncating
# the last ":octetpair" from the compressed-form
# remote IPv6 host address string, until a match is
# found in the access table, or until further trunca-
# tion is not possible.
#
# NOTE: use the cidr lookup table type to specify
# network/netmask patterns. See cidr_table(5) for
# details.
#
# IPv6 support is available in Postfix 2.2 and later.
#
# ACCEPT ACTIONS
# OK Accept the address etc. that matches the pattern.
#
# all-numerical
# An all-numerical result is treated as OK. This for-
# mat is generated by address-based relay authoriza-
# tion schemes such as pop-before-smtp.
#
# For other accept actions, see "OTHER ACTIONS" below.
#
# REJECT ACTIONS
# Postfix version 2.3 and later support enhanced status
# codes as defined in RFC 3463. When no code is specified
# at the beginning of the text below, Postfix inserts a
# default enhanced status code of "5.7.1" in the case of
# reject actions, and "4.7.1" in the case of defer actions.
# See "ENHANCED STATUS CODES" below.
#
# 4NN text
#
# 5NN text
# Reject the address etc. that matches the pattern,
# and respond with the numerical three-digit code and
# text. 4NN means "try again later", while 5NN means
# "do not try again".
#
# The following responses have special meaning for
# the Postfix SMTP server:
#
# 421 text (Postfix 2.3 and later)
#
# 521 text (Postfix 2.6 and later)
# After responding with the numerical
# three-digit code and text, disconnect imme-
# diately from the SMTP client. This frees up
# SMTP server resources so that they can be
# made available to another SMTP client.
#
# Note: The "521" response should be used only
# with botnets and other malware where inter-
# operability is of no concern. The "send 521
# and disconnect" behavior is NOT defined in
# the SMTP standard.
#
# REJECT optional text...
# Reject the address etc. that matches the pattern.
# Reply with "$access_map_reject_code optional
# text..." when the optional text is specified, oth-
# erwise reply with a generic error response message.
#
# DEFER optional text...
# Reject the address etc. that matches the pattern.
# Reply with "$access_map_defer_code optional
# text..." when the optional text is specified, oth-
# erwise reply with a generic error response message.
#
# This feature is available in Postfix 2.6 and later.
#
# DEFER_IF_REJECT optional text...
# Defer the request if some later restriction would
# result in a REJECT action. Reply with
# "$access_map_defer_code 4.7.1 optional text..."
# when the optional text is specified, otherwise
# reply with a generic error response message.
#
# Prior to Postfix 2.6, the SMTP reply code is 450.
#
# This feature is available in Postfix 2.1 and later.
#
# DEFER_IF_PERMIT optional text...
# Defer the request if some later restriction would
# result in a an explicit or implicit PERMIT action.
# Reply with "$access_map_defer_code 4.7.1 optional
# text..." when the optional text is specified, oth-
# erwise reply with a generic error response message.
#
# Prior to Postfix 2.6, the SMTP reply code is 450.
#
# This feature is available in Postfix 2.1 and later.
#
# For other reject actions, see "OTHER ACTIONS" below.
#
# OTHER ACTIONS
# restriction...
# Apply the named UCE restriction(s) (permit, reject,
# reject_unauth_destination, and so on).
#
# BCC user@domain
# Send one copy of the message to the specified
# recipient.
#
# If multiple BCC actions are specified within the
# same SMTP MAIL transaction, with Postfix 3.0 only
# the last action will be used.
#
# This feature is available in Postfix 3.0 and later.
#
# DISCARD optional text...
# Claim successful delivery and silently discard the
# message. Log the optional text if specified, oth-
# erwise log a generic message.
#
# Note: this action currently affects all recipients
# of the message. To discard only one recipient
# without discarding the entire message, use the
# transport(5) table to direct mail to the discard(8)
# service.
#
# This feature is available in Postfix 2.0 and later.
#
# DUNNO Pretend that the lookup key was not found. This
# prevents Postfix from trying substrings of the
# lookup key (such as a subdomain name, or a network
# address subnetwork).
#
# This feature is available in Postfix 2.0 and later.
#
# FILTER transport:destination
# After the message is queued, send the entire mes-
# sage through the specified external content filter.
# The transport name specifies the first field of a
# mail delivery agent definition in master.cf; the
# syntax of the next-hop destination is described in
# the manual page of the corresponding delivery
# agent. More information about external content
# filters is in the Postfix FILTER_README file.
#
# Note 1: do not use $number regular expression sub-
# stitutions for transport or destination unless you
# know that the information has a trusted origin.
#
# Note 2: this action overrides the main.cf con-
# tent_filter setting, and affects all recipients of
# the message. In the case that multiple FILTER
# actions fire, only the last one is executed.
#
# Note 3: the purpose of the FILTER command is to
# override message routing. To override the recipi-
# ent's transport but not the next-hop destination,
# specify an empty filter destination (Postfix 2.7
# and later), or specify a transport:destination that
# delivers through a different Postfix instance
# (Postfix 2.6 and earlier). Other options are using
# the recipient-dependent transport_maps or the sen-
# der-dependent sender_dependent_default_transport-
# _maps features.
#
# This feature is available in Postfix 2.0 and later.
#
# HOLD optional text...
# Place the message on the hold queue, where it will
# sit until someone either deletes it or releases it
# for delivery. Log the optional text if specified,
# otherwise log a generic message.
#
# Mail that is placed on hold can be examined with
# the postcat(1) command, and can be destroyed or
# released with the postsuper(1) command.
#
# Note: use "postsuper -r" to release mail that was
# kept on hold for a significant fraction of $maxi-
# mal_queue_lifetime or $bounce_queue_lifetime, or
# longer. Use "postsuper -H" only for mail that will
# not expire within a few delivery attempts.
#
# Note: this action currently affects all recipients
# of the message.
#
# This feature is available in Postfix 2.0 and later.
#
# PREPEND headername: headervalue
# Prepend the specified message header to the mes-
# sage. When more than one PREPEND action executes,
# the first prepended header appears before the sec-
# ond etc. prepended header.
#
# Note: this action must execute before the message
# content is received; it cannot execute in the con-
# text of smtpd_end_of_data_restrictions.
#
# This feature is available in Postfix 2.1 and later.
#
# REDIRECT user@domain
# After the message is queued, send the message to
# the specified address instead of the intended
# recipient(s). When multiple REDIRECT actions fire,
# only the last one takes effect.
#
# Note: this action overrides the FILTER action, and
# currently overrides all recipients of the message.
#
# This feature is available in Postfix 2.1 and later.
#
# INFO optional text...
# Log an informational record with the optional text,
# together with client information and if available,
# with helo, sender, recipient and protocol informa-
# tion.
#
# This feature is available in Postfix 3.0 and later.
#
# WARN optional text...
# Log a warning with the optional text, together with
# client information and if available, with helo,
# sender, recipient and protocol information.
#
# This feature is available in Postfix 2.1 and later.
#
# ENHANCED STATUS CODES
# Postfix version 2.3 and later support enhanced status
# codes as defined in RFC 3463. When an enhanced status
# code is specified in an access table, it is subject to
# modification. The following transformations are needed
# when the same access table is used for client, helo,
# sender, or recipient access restrictions; they happen
# regardless of whether Postfix replies to a MAIL FROM, RCPT
# TO or other SMTP command.
#
# o When a sender address matches a REJECT action, the
# Postfix SMTP server will transform a recipient DSN
# status (e.g., 4.1.1-4.1.6) into the corresponding
# sender DSN status, and vice versa.
#
# o When non-address information matches a REJECT
# action (such as the HELO command argument or the
# client hostname/address), the Postfix SMTP server
# will transform a sender or recipient DSN status
# into a generic non-address DSN status (e.g.,
# 4.0.0).
#
# REGULAR EXPRESSION TABLES
# This section describes how the table lookups change when
# the table is given in the form of regular expressions. For
# a description of regular expression lookup table syntax,
# see regexp_table(5) or pcre_table(5).
#
# Each pattern is a regular expression that is applied to
# the entire string being looked up. Depending on the appli-
# cation, that string is an entire client hostname, an
# entire client IP address, or an entire mail address. Thus,
# no parent domain or parent network search is done,
# user@domain mail addresses are not broken up into their
# user@ and domain constituent parts, nor is user+foo broken
# up into user and foo.
#
# Patterns are applied in the order as specified in the ta-
# ble, until a pattern is found that matches the search
# string.
#
# Actions are the same as with indexed file lookups, with
# the additional feature that parenthesized substrings from
# the pattern can be interpolated as $1, $2 and so on.
#
# TCP-BASED TABLES
# This section describes how the table lookups change when
# lookups are directed to a TCP-based server. For a descrip-
# tion of the TCP client/server lookup protocol, see tcp_ta-
# ble(5). This feature is not available up to and including
# Postfix version 2.4.
#
# Each lookup operation uses the entire query string once.
# Depending on the application, that string is an entire
# client hostname, an entire client IP address, or an entire
# mail address. Thus, no parent domain or parent network
# search is done, user@domain mail addresses are not broken
# up into their user@ and domain constituent parts, nor is
# user+foo broken up into user and foo.
#
# Actions are the same as with indexed file lookups.
#
# EXAMPLE
# The following example uses an indexed file, so that the
# order of table entries does not matter. The example per-
# mits access by the client at address 1.2.3.4 but rejects
# all other clients in 1.2.3.0/24. Instead of hash lookup
# tables, some systems use dbm. Use the command "postconf
# -m" to find out what lookup tables Postfix supports on
# your system.
#
# /etc/postfix/main.cf:
# smtpd_client_restrictions =
# check_client_access hash:/etc/postfix/access
#
# /etc/postfix/access:
# 1.2.3 REJECT
# 1.2.3.4 OK
#
# Execute the command "postmap /etc/postfix/access" after
# editing the file.
#
# BUGS
# The table format does not understand quoting conventions.
#
# SEE ALSO
# postmap(1), Postfix lookup table manager
# smtpd(8), SMTP server
# postconf(5), configuration parameters
# transport(5), transport:nexthop syntax
#
# README FILES
# Use "postconf readme_directory" or "postconf html_direc-
# tory" to locate this information.
# SMTPD_ACCESS_README, built-in SMTP server access control
# DATABASE_README, Postfix lookup table overview
#
# LICENSE
# The Secure Mailer license must be distributed with this
# software.
#
# AUTHOR(S)
# Wietse Venema
# IBM T.J. Watson Research
# P.O. Box 704
# Yorktown Heights, NY 10598, USA
#
# Wietse Venema
# Google, Inc.
# 111 8th Avenue
# New York, NY 10011, USA
#
# ACCESS(5)
Download the raw file with wget or curl
wget -O access.example http://exampleconfig.com/static/raw/postfix/rhel8/etc/postfix/access
curl http://exampleconfig.com/static/raw/postfix/rhel8/etc/postfix/access > access.example
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