ACCESS(5)

NAME
access - format of Postfix access table

SYNOPSIS
postmap /etc/postfix/access
postmap -q "string" /etc/postfix/access
postmap -q - /etc/postfix/access <inputfile

DESCRIPTION
The optional access table directs the Postfix SMTP server to selectively reject or accept mail. Access can be allowed or denied for specific host names, domain names, networks, host network addresses or mail addresses. Normally, the access 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 in order to rebuild the indexed file after changing the access table. 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 regular-expression map where patterns are given as regular expressions. In that case, the lookups are done in a slightly different way as described below.

TABLE FORMAT
The format of the access table 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 logical line.

EMAIL 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:

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 configuration setting. Otherwise, specify .domain.tld (note the initial dot) in order to match subdomains.

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.

ADDRESS EXTENSION
When a mail address localpart contains the optional recipient 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 configuration setting. Otherwise, specify .domain.tld (note the initial dot) in order to match subdomains.

net.work.addr.ess

net.work.addr

net.work

net Matches any host address in the specified network. A network address is a sequence of one or more octets separated by ".".

ACTIONS

[45]NN text
    Reject the address etc. that matches the pattern, and respond with the numerical code and text.

REJECT

REJECT optional text...
    Reject the address etc. that matches the pattern. Reply with $reject_code optional text... when the optional text is specified, otherwise reply with a generic error response message.

OK  Accept the address etc. that matches the pattern.

all-numerical
    An all-numerical result is treated as OK. This format is generated by address-based relay authorization schemes.

DUNNO
    Pretend that the lookup key was not found in this table. This prevents Postfix from trying substrings of the lookup key (such as a subdomain name, or a network address subnetwork).

HOLD

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: this action currently affects all recipients of the message.

DISCARD

DISCARD optional text...
    Claim successful delivery and silently discard the message. Log the optional text if specified, otherwise log a generic message.

    Note: this action currently affects all recipients of the message.

FILTER transport:destination
    After the message is queued, send the entire message through a content filter. More information about content filters is in the Postfix FILTER_README file.

    Note: this action overrides the main.cf content_filter setting, and currently affects all recipients of the message.

restriction...
    Apply the named UCE restriction(s) (permit, reject, reject_unauth_destination, and so on).

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 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. Patterns are applied in the order as specified in the table, 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.

BUGS
The table format does not understand quoting conventions.

SEE ALSO
postmap(1) create mapping table
smtpd(8) smtp server
pcre_table(5) format of PCRE tables
regexp_table(5) format of POSIX regular expression tables

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