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RReejjeeccttiinngg UUnnkknnoowwnn LLooccaall RReecciippiieennttss wwiitthh PPoossttffiixx
-------------------------------------------------------------------------------
IInnttrroodduuccttiioonn
As of Postfix version 2.0, the Postfix SMTP server rejects mail for unknown
recipients in local domains (domains that match $mydestination or the IP
addresses in $inet_interfaces or $proxy_interfaces) with "User unknown in local
recipient table". This feature was optional with earlier Postfix versions.
The good news is that this keeps undeliverable mail out of your queue, so that
your mail queue is not clogged up with undeliverable MAILER-DAEMON messages.
The bad news is that it may cause mail to be rejected when you upgrade from a
Postfix system that was not configured to reject mail for unknown local
recipients.
This document describes what steps are needed in order to reject unknown local
recipients correctly.
* Configuring local_recipient_maps in main.cf
* When you need to change the local_recipient_maps setting in main.cf
* Local recipient table format
CCoonnffiigguurriinngg llooccaall__rreecciippiieenntt__mmaappss iinn mmaaiinn..ccff
The local_recipient_maps parameter specifies lookup tables with all names or
addresses of local recipients. A recipient address is local when its domain
matches $mydestination, $inet_interfaces or $proxy_interfaces. If a local
username or address is not listed in $local_recipient_maps, then the Postfix
SMTP server will reject the address with "User unknown in local recipient
table". Other Postfix interfaces may still accept an "unknown" recipient.
The default setting, shown below, assumes that you use the default Postfix
local(8) delivery agent for local delivery, where recipients are either UNIX
accounts or local aliases:
/etc/postfix/main.cf:
local_recipient_maps = proxy:unix:passwd.byname $alias_maps
To turn off unknown local recipient rejects by the SMTP server, specify:
/etc/postfix/main.cf:
local_recipient_maps =
That is, an empty value. With this setting, the Postfix SMTP server will not
reject mail with "User unknown in local recipient table". DDoonn''tt ddoo tthhiiss oonn
ssyysstteemmss tthhaatt rreecceeiivvee mmaaiill ddiirreeccttllyy ffrroomm tthhee IInntteerrnneett.. WWiitthh ttooddaayy''ss wwoorrmmss aanndd
vviirruusseess,, PPoossttffiixx wwiillll bbeeccoommee aa bbaacckkssccaatttteerr ssoouurrccee:: iitt aacccceeppttss mmaaiill ffoorr nnoonn--
eexxiisstteenntt rreecciippiieennttss aanndd tthheenn ttrriieess ttoo rreettuurrnn tthhaatt mmaaiill aass ""uunnddeelliivveerraabbllee"" ttoo
tthhee oofftteenn ffoorrggeedd sseennddeerr aaddddrreessss.
WWhheenn yyoouu nneeeedd ttoo cchhaannggee tthhee llooccaall__rreecciippiieenntt__mmaappss sseettttiinngg iinn mmaaiinn..ccff
* Problem: you don't use the default Postfix local(8) delivery agent for
domains matching $mydestination, $inet_interfaces, or $proxy_interfaces.
For example, you redefined the "local_transport" setting in main.cf.
Solution: your local_recipient_maps setting needs to specify a database
that lists all the known user names or addresses for that delivery agent.
For example, if you deliver users in $mydestination etc. domains via the
virtual(8) delivery agent, specify:
/etc/postfix/main.cf
mydestination = $myhostname localhost.$mydomain localhost ...
local_transport = virtual
local_recipient_maps = $virtual_mailbox_maps
If you use a different delivery agent for $mydestination etc. domains, see
the section "Local recipient table format" below for a description of how
the table should be populated.
* Problem: you use the mailbox_transport or fallback_transport feature of the
Postfix local(8) delivery agent in order to deliver mail to non-UNIX
accounts.
Solution: you need to add the database that lists the non-UNIX users:
/etc/postfix/main.cf
local_recipient_maps = proxy:unix:passwd.byname, $alias_maps,
<the database with non-UNIX accounts>
See the section "Local recipient table format" below for a description of
how the table should be populated.
* Problem: you use the luser_relay feature of the Postfix local delivery
agent.
Solution: you must disable the local_recipient_maps feature completely, so
that Postfix accepts mail for all local addresses:
/etc/postfix/main.cf
local_recipient_maps =
LLooccaall rreecciippiieenntt ttaabbllee ffoorrmmaatt
If you use local files in postmap(1) format, then local_recipient_maps expects
the following table format:
* In the left-hand side, specify a bare username, an "@domain.tld" wild-card,
or specify a complete "user@domain.tld" address.
* You have to specify something on the right-hand side of the table, but the
value is ignored by local_recipient_maps.
If you use lookup tables based on NIS, LDAP, MYSQL, or PGSQL, then
local_recipient_maps does the same queries as for local files in postmap(1)
format, and expects the same results.
With regular expression tables, Postfix only queries with the full recipient
address, and not with the bare username or the "@domain.tld" wild-card.
NOTE: a lookup table should always return a result when the address exists, and
should always return "not found" when the address does not exist. In
particular, a zero-length result does not count as a "not found" result.
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