NetBSD/gnu/dist/postfix/html/transport.5.html

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TRANSPORT(5) TRANSPORT(5)
<b>NAME</b>
transport - format of Postfix transport table
<b>SYNOPSIS</b>
<b>postmap</b> <b>/etc/postfix/transport</b>
<b>DESCRIPTION</b>
The optional <b>transport</b> table specifies a mapping from
domain hierarchies to message delivery transports and/or
relay hosts. The mapping is used by the <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a>
daemon.
Normally, the <b>transport</b> table is specified as a text file
that serves as input to the <a href="postmap.1.html"><b>postmap</b>(1)</a> command. The
result, an indexed file in <b>dbm</b> or <b>db</b> format, is used for
fast searching by the mail system. Execute the command
<b>postmap</b> <b>/etc/postfix/transport</b> 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 expres-
sions. In that case, the lookups are done in a slightly
different way as described below.
<b>TABLE</b> <b>FORMAT</b>
The format of the transport table is as follows:
blanks and comments
Blank lines are ignored, as are lines beginning
with `#'.
leading whitespace
Lines that begin with whitespace continue the pre-
vious line.
<i>pattern</i> <i>result</i>
When <i>pattern</i> matches the domain, use the corre-
sponding <i>result</i>.
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:
<i>domain</i> <i>transport</i>:<i>nexthop</i>
Mail for <i>domain</i> is delivered through <i>transport</i> to
<i>nexthop</i>.
<i>.domain</i> <i>transport</i>:<i>nexthop</i>
Mail for any subdomain of <i>domain</i> is delivered
through <i>transport</i> to <i>nexthop</i>.
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TRANSPORT(5) TRANSPORT(5)
Note: transport map entries take precedence over domains
specified in the <b>mydestination</b> parameter. If you use the
optional transport map, it may be safer to specify
explicit entries for all domains specified in <b>mydestina-</b>
<b>tion</b>, for example:
<b>hostname.my.domain</b> <b>local:</b>
<b>localhost.my.domain</b> <b>local:</b>
The interpretation of the <i>nexthop</i> field is transport
dependent. In the case of SMTP, specify <i>host</i>:<i>service</i> for a
non-default server port, and use [<i>host</i>] or [<i>host</i>]:<i>port</i> in
order to disable MX (mail exchanger) DNS lookups. The []
form can also be used with IP addresses instead of host-
names.
<b>EXAMPLES</b>
In order to send mail for <b>foo.org</b> and its subdomains via
the <b>uucp</b> transport to the UUCP host named <b>foo</b>:
<b>foo.org</b> <b>uucp:foo</b>
<b>.foo.org</b> <b>uucp:foo</b>
When no <i>nexthop</i> host name is specified, the destination
domain name is used instead. For example, the following
directs mail for <i>user</i>@<b>foo.org</b> via the <b>slow</b> transport to a
mail exchanger for <b>foo.org</b>. The <b>slow</b> transport could be
something that runs at most one delivery process at a
time:
<b>foo.org</b> <b>slow:</b>
When no <i>transport</i> is specified, the default transport is
used, as specified via the <b>default</b><i>_</i><b>transport</b> configuration
parameter. The following sends all mail for <b>foo.org</b> and
its subdomains to host <b>gateway.foo.org</b>:
<b>foo.org</b> <b>:[gateway.foo.org]</b>
<b>.foo.org</b> <b>:[gateway.foo.org]</b>
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 <i>host-</i>
<i>name</i>:<i>service</i> instead of just a host:
<b>foo.org</b> <b>smtp:bar.org:2025</b>
This directs mail for <i>user</i>@<b>foo.org</b> to host <b>bar.org</b> port
<b>2025</b>. Instead of a numerical port a symbolic name may be
used. Specify [] around the hostname in order to disable
MX lookups.
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TRANSPORT(5) TRANSPORT(5)
The error mailer can be used to bounce mail:
<b>.foo.org</b> <b>error:mail</b> <b>for</b> <b>*.foo.org</b> <b>is</b> <b>not</b> <b>deliv-</b>
<b>erable</b>
This causes all mail for <i>user</i>@<i>anything</i><b>.foo.org</b> to be
bounced.
<b>REGULAR</b> <b>EXPRESSION</b> <b>TABLES</b>
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 <a href="regexp_table.5.html"><b>regexp</b><i>_</i><b>table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre</b><i>_</i><b>table</b>(5)</a>.
Each pattern is a regular expression that is applied to
the entire domain being looked up. Thus, <i>some.domain.hier-</i>
<i>archy</i> 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 normal indexed file lookups,
with the additional feature that parenthesized substrings
from the pattern can be interpolated as <b>$1</b>, <b>$2</b> and so on.
<b>CONFIGURATION</b> <b>PARAMETERS</b>
The following <b>main.cf</b> parameters are especially relevant
to this topic. See the Postfix <b>main.cf</b> file for syntax
details and for default values. Use the <b>postfix</b> <b>reload</b>
command after a configuration change.
<b>transport</b><i>_</i><b>maps</b>
List of transport lookup tables.
Other parameters of interest:
<b>default</b><i>_</i><b>transport</b>
The transport to use when no transport is explic-
itly specified.
<b>relayhost</b>
The default host to send to when no transport table
entry matches.
<b>SEE</b> <b>ALSO</b>
<a href="postmap.1.html">postmap(1)</a> create mapping table
<a href="trivial-rewrite.8.html">trivial-rewrite(8)</a> rewrite and resolve addresses
<a href="pcre_table.5.html">pcre_table(5)</a> format of PCRE tables
<a href="regexp_table.5.html">regexp_table(5)</a> format of POSIX regular expression tables
<b>LICENSE</b>
The Secure Mailer license must be distributed with this
software.
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TRANSPORT(5) TRANSPORT(5)
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
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