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 regular-
expression map where patterns are given as regular expres-
sions, 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 (note that this is the default
for some versions of Postfix). 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.
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. Otherwise, specify .domain.tld
(note the initial dot) in order to match subdo-
mains.
net.work.addr.ess
net.work.addr
net.work
net Matches the specified IPv4 host address or subnet-
work. An IPv4 host address is a sequence of four
decimal octets separated by ".".
Subnetworks are matched by repeatedly truncating
the last ".octet" from the remote IPv4 host address
string until a match is found in the access table,
or until further truncation is not possible.
NOTE 1: The access map lookup key must be in canon-
ical form: do not specify unnecessary null charac-
ters, and do not enclose network address informa-
tion with "[]" characters.
NOTE 2: 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 the specified IPv6 host address or subnet-
work. An IPv6 host address is a sequence of three
to eight hexadecimal octet pairs separated by ":".
Subnetworks are matched by repeatedly truncating
the last ":octetpair" from the remote IPv6 host
address string until a match is found in the access
table, or until further truncation is not possible.
NOTE 1: the truncation and comparison are done with
the string representation of the IPv6 host address.
Thus, not all the ":" subnetworks will be tried.
NOTE 2: The access map lookup key must be in canon-
ical form: do not specify unnecessary null charac-
ters, and do not enclose network address informa-
tion with "[]" characters.
NOTE 3: 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.
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 reply code "421" causes Postfix to disconnect
immediately (Postfix version 2.3 and later).
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.
DEFER_IF_REJECT optional text...
Defer the request if some later restriction would
result in a REJECT action. Reply with "450 4.7.1
optional text... when the optional text is speci-
fied, otherwise reply with a generic error response
message.
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 "450 4.7.1 optional text... when the
optional text is specified, otherwise reply with a
generic error response message.
This feature is available in Postfix 2.1 and later.
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, only the last action
will be used.
This feature is not part of the stable Postfix
release.
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:destination syntax is described in
the transport(5) manual page. More information
about external content filters is in the Postfix
FILTER_README file.
Note: this action overrides the content_filter set-
ting, and currently affects all recipients of the
message.
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).
Note: this action overrides the FILTER action, and
currently affects all recipients of the message.
This feature is available in Postfix 2.1 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. width="203" heigh
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 reply code "421" causes Postfix to disconnect
immediately (Postfix version 2.3 and later).
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.
DEFER_IF_REJECT optional text...
Defer the request if some later restriction would
result in a REJECT action. Reply with "450 4.7.1
optional text... when the optional text is speci-
fied, otherwise reply with a generic error response
message.
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 "450 4.7.1 optional text... when the
optional text is specified, otherwise reply with a
generic error response message.
This feature is available in Postfix 2.1 and later.
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, only the last action
will be used.
This feature is not part of the stable Postfix
release.
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:destination syntax is described in
the transport(5)