<header>Transport mapping</header>

The optional transport file specifies a mapping from domain hierarchies to
message delivery transports and/or relay hosts. The mapping is used by the
trivial-rewrite(8) daemon.

<p>

The format of the transport table is as follows:
<ul>
<li><b><tt>domain</tt></b> mapped to.. <b><tt>transport:nexthop</tt></b>: Mail
for domain is delivered through transport to nexthop.
<li><b><tt>.domain</tt></b> mapped to.. <b><tt>transport:nexthop</tt></b>: Mail
for any subdomain of domain is delivered through transport to nexthop.
</ul>

Note: transport map entries take precedence over domains specified in the
<tt>mydestination</tt> parameter. If you use the optional transport map, it may
be safer to specify explicit entries for all domains specified in
mydestination, for example:
<ul>
<li><tt>hostname.my.domain</tt> ... <tt>local:</tt>
<li><tt>localhost.my.domain</tt> ... <tt>local:</tt>
</ul>

The interpretation of the nexthop field is transport dependent. In the case of
SMTP, specify <tt>host:service</tt> for a non-default server port, and use
<tt>[host]</tt> or <tt>[host:port]</tt> in order to disable MX (mail exchanger)
DNS lookups. The <tt>[]</tt> form can also be used with IP addresses instead of
hostnames.

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