.TH TRANSPORT 5 .ad .fi .SH NAME transport \- format of Postfix transport table .SH SYNOPSIS .na .nf \fBpostmap /etc/postfix/transport\fR \fBpostmap -q "\fIstring\fB" /etc/postfix/transport\fR \fBpostmap -q - /etc/postfix/transport <\fIinputfile\fR .SH DESCRIPTION .ad .fi The optional \fBtransport\fR table specifies a mapping from email addresses to message delivery transports and/or relay hosts. The mapping is used by the \fBtrivial-rewrite\fR(8) daemon. Normally, the \fBtransport\fR table is specified as a text file that serves as input to the \fBpostmap\fR(1) command. The result, an indexed file in \fBdbm\fR or \fBdb\fR format, is used for fast searching by the mail system. Execute the command \fBpostmap /etc/postfix/transport\fR in order to rebuild the indexed file after changing the transport 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 in section "REGULAR EXPRESSION TABLES". .SH TABLE FORMAT .na .nf .ad .fi The format of the transport table is as follows: .IP "\fIpattern result\fR" When \fIpattern\fR matches the recipient address or domain, use the corresponding \fIresult\fR. .IP "blank lines and comments" Empty lines and whitespace-only lines are ignored, as are lines whose first non-whitespace character is a `#'. .IP "multi-line text" A logical line starts with non-whitespace text. A line that starts with whitespace continues a logical line. .PP The \fIpattern\fR specifies an email address, a domain name, or a domain name hierarchy, as described in section "TABLE LOOKUP". The \fIresult\fR is of the form \fItransport\fB:\fInexthop\fR. The \fItransport\fR field specifies a mail delivery transport such as \fBsmtp\fR or \fBlocal\fR. The \fInexthop\fR field specifies where and how to deliver mail. More details are given in section "RESULT FORMAT". .SH TABLE LOOKUP .na .nf .ad .fi 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: .IP "\fIuser+extension@domain transport\fR:\fInexthop\fR" Mail for \fIuser+extension@domain\fR is delivered through \fItransport\fR to \fInexthop\fR. .IP "\fIuser@domain transport\fR:\fInexthop\fR" Mail for \fIuser@domain\fR is delivered through \fItransport\fR to \fInexthop\fR. .IP "\fIdomain transport\fR:\fInexthop\fR" Mail for \fIdomain\fR is delivered through \fItransport\fR to \fInexthop\fR. .IP "\fI.domain transport\fR:\fInexthop\fR" Mail for any subdomain of \fIdomain\fR is delivered through \fItransport\fR to \fInexthop\fR. This applies only when the string \fBtransport_maps\fR is not listed in the \fBparent_domain_matches_subdomains\fR configuration setting. Otherwise, a domain name matches itself and its subdomains. .PP Note 1: the special pattern \fB*\fR represents any address (i.e. it functions as the wild-card pattern). Note 2: the null recipient address is looked up as \fB$empty_address_recipient\fR@\fB$myhostname\fR (default: mailer-daemon@hostname). .SH RESULT FORMAT .na .nf .ad .fi The transport field specifies the name of a mail delivery transport (the first name of a mail delivery service entry in the Postfix \fBmaster.cf\fR file). The interpretation of the nexthop field is transport dependent. In the case of SMTP, specify \fIhost\fR:\fIservice\fR for a non-default server port, and use [\fIhost\fR] or [\fIhost\fR]:\fIport\fR in order to disable MX (mail exchanger) DNS lookups. The [] form is required when you specify an IP address instead of a hostname. A null \fItransport\fR and null \fInexthop\fR result means "do not change": use the delivery transport and nexthop information that would be used when the entire transport table did not exist. A non-null \fItransport\fR field with a null \fInexthop\fR field resets the nexthop information to the recipient domain. A null \fItransport\fR field with non-null \fInexthop\fR field does not modify the transport information. .SH EXAMPLES .na .nf .ad .fi In order to deliver internal mail directly, while using a mail relay for all other mail, specify a null entry for internal destinations (do not change the delivery transport or the nexthop information) and specify a wildcard for all other destinations. .ti +5 \fB\&my.domain :\fR .ti +5 \fB\&.my.domain :\fR .ti +5 \fB* smtp:outbound-relay.my.domain\fR In order to send mail for \fBfoo.org\fR and its subdomains via the \fBuucp\fR transport to the UUCP host named \fBfoo\fR: .ti +5 \fBfoo.org uucp:foo\fR .ti +5 \fB\&.foo.org uucp:foo\fR When no nexthop host name is specified, the destination domain name is used instead. For example, the following directs mail for \fIuser\fR@\fBfoo.org\fR via the \fBslow\fR transport to a mail exchanger for \fBfoo.org\fR. The \fBslow\fR transport could be something that runs at most one delivery process at a time: .ti +5 \fBfoo.org slow:\fR When no transport is specified, Postfix uses the transport that matches the address domain class (see TRANSPORT FIELD discussion above). The following sends all mail for \fBfoo.org\fR and its subdomains to host \fBgateway.foo.org\fR: .ti +5 \fBfoo.org :[gateway.foo.org]\fR .ti +5 \fB\&.foo.org :[gateway.foo.org]\fR In the above example, the [] are used to suppress MX lookups. The result would likely point to your local machine. In the case of delivery via SMTP, one may specify \fIhostname\fR:\fIservice\fR instead of just a host: .ti +5 \fBfoo.org smtp:bar.org:2025\fR This directs mail for \fIuser\fR@\fBfoo.org\fR to host \fBbar.org\fR port \fB2025\fR. Instead of a numerical port a symbolic name may be used. Specify [] around the hostname in order to disable MX lookups. The error mailer can be used to bounce mail: .ti +5 \fB\&.foo.org error:mail for *.foo.org is not deliverable\fR This causes all mail for \fIuser\fR@\fIanything\fB.foo.org\fR to be bounced. .SH REGULAR EXPRESSION TABLES .na .nf .ad .fi 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 \fBregexp_table\fR(5) or \fBpcre_table\fR(5). Each pattern is a regular expression that is applied to the entire domain being looked up. Thus, \fIsome.domain.hierarchy\fR is not broken up into parent domains. Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string. Results are the same as with indexed file lookups, with the additional feature that parenthesized substrings from the pattern can be interpolated as \fB$1\fR, \fB$2\fR and so on. .SH CONFIGURATION PARAMETERS .na .nf .ad .fi The following \fBmain.cf\fR parameters are especially relevant to this topic. See the Postfix \fBmain.cf\fR file for syntax details and for default values. Use the \fBpostfix reload\fR command after a configuration change. .IP \fBempty_address_recipient\fR The address that is looked up instead of the null sender address. .IP \fBparent_domain_matches_subdomains\fR List of Postfix features that use \fIdomain.tld\fR patterns to match \fIsub.domain.tld\fR (as opposed to requiring \fI.domain.tld\fR patterns). .IP \fBtransport_maps\fR List of transport lookup tables. .SH SEE ALSO .na .nf postmap(1) create mapping table trivial-rewrite(8) rewrite and resolve addresses pcre_table(5) format of PCRE tables regexp_table(5) format of POSIX regular expression tables .SH LICENSE .na .nf .ad .fi The Secure Mailer license must be distributed with this software. .SH AUTHOR(S) .na .nf Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA