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<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
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<title> Postfix manual - transport(5) </title>
</head> <body> <pre>
TRANSPORT(5)                                                      TRANSPORT(5)

<b>NAME</b>
       transport - Postfix transport table format

<b>SYNOPSIS</b>
       <b>postmap /etc/postfix/transport</b>

       <b>postmap -q "</b><i>string</i><b>" /etc/postfix/transport</b>

       <b>postmap -q - /etc/postfix/transport</b> &lt;<i>inputfile</i>

<b>DESCRIPTION</b>
       The   optional  <a href="transport.5.html"><b>transport</b>(5)</a>  table  specifies  a  mapping  from  email
       addresses to message delivery  transports  and  next-hop  destinations.
       Message  delivery  transports  such as <b>local</b> or <b>smtp</b> are defined in the
       <a href="master.5.html"><b>master.cf</b></a> file, and next-hop destinations are typically hosts or domain
       names. The table is searched by the <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a> daemon.

       This  mapping overrides the default <i>transport</i>:<i>nexthop</i> selection that is
       built into Postfix:

       <b><a href="postconf.5.html#local_transport">local_transport</a> (default: <a href="local.8.html">local</a>:$<a href="postconf.5.html#myhostname">myhostname</a>)</b>
              This is the default for final delivery to  domains  listed  with
              <b><a href="postconf.5.html#mydestination">mydestination</a></b>,  and  for  [<i>ipaddress</i>]  destinations  that  match
              <b>$<a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b> or <b>$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>. The default <i>nexthop</i>  des-
              tination is the MTA hostname.

       <b><a href="postconf.5.html#virtual_transport">virtual_transport</a> (default: <a href="virtual.8.html">virtual</a>:)</b>
              This  is  the  default for final delivery to domains listed with
              <b><a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a></b>. The default <i>nexthop</i> destination is  the
              recipient domain.

       <b><a href="postconf.5.html#relay_transport">relay_transport</a> (default: relay:)</b>
              This  is  the default for remote delivery to domains listed with
              <b><a href="postconf.5.html#relay_domains">relay_domains</a></b>. In order of decreasing  precedence,  the  <i>nexthop</i>
              destination   is   taken   from  <b><a href="postconf.5.html#relay_transport">relay_transport</a></b>,  <b><a href="postconf.5.html#sender_dependent_relayhost_maps">sender_depen</a>-</b>
              <b><a href="postconf.5.html#sender_dependent_relayhost_maps">dent_relayhost_maps</a></b>, <b><a href="postconf.5.html#relayhost">relayhost</a></b>, or from the recipient domain.

       <b><a href="postconf.5.html#default_transport">default_transport</a> (default: <a href="smtp.8.html">smtp</a>:)</b>
              This is the default for remote delivery to  other  destinations.
              In  order  of  decreasing precedence, the <i>nexthop</i> destination is
              taken       from        <b><a href="postconf.5.html#sender_dependent_default_transport_maps">sender_dependent_default_transport_maps</a>,</b>
              <b><a href="postconf.5.html#default_transport">default_transport</a></b>,  <b><a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a></b>,  <b><a href="postconf.5.html#relayhost">relayhost</a></b>,
              or from the recipient domain.

       Normally, the <a href="transport.5.html"><b>transport</b>(5)</a> 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  /etc/postfix/transport</b>"  to rebuild an
       indexed file after changing the corresponding 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,  or  lookups  can  be
       directed  to a TCP-based server. In those case, the lookups are done in
       a slightly different way as described below under  "REGULAR  EXPRESSION
       TABLES" or "TCP-BASED TABLES".

<b>CASE FOLDING</b>
       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  <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>: whose lookup fields can match both upper and
       lower case.

<b>TABLE FORMAT</b>
       The input format for the <a href="postmap.1.html"><b>postmap</b>(1)</a> command is as follows:

       <i>pattern result</i>
              When <i>pattern</i> matches the recipient address or  domain,  use  the
              corresponding <i>result</i>.

       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 logical line.

       The <i>pattern</i> specifies an email address, a domain name, or a domain name
       hierarchy, as described in section "TABLE SEARCH ORDER".

       The <i>result</i> is of the form <i>transport:nexthop</i> and specifies how or  where
       to deliver mail. This is described in section "RESULT FORMAT".

<b>TABLE SEARCH ORDER</b>
       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>user+extension@domain transport</i>:<i>nexthop</i>
              Deliver mail for <i>user+extension@domain</i> through <i>transport</i> to <i>nex-</i>
              <i>thop</i>.

       <i>user@domain transport</i>:<i>nexthop</i>
              Deliver mail for <i>user@domain</i> through <i>transport</i> to <i>nexthop</i>.

       <i>domain transport</i>:<i>nexthop</i>
              Deliver mail for <i>domain</i> through <i>transport</i> to <i>nexthop</i>.

       <i>.domain transport</i>:<i>nexthop</i>
              Deliver mail for any subdomain of <i>domain</i>  through  <i>transport</i>  to
              <i>nexthop</i>. This applies only when the string <b><a href="postconf.5.html#transport_maps">transport_maps</a></b> is not
              listed  in  the  <b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a></b>  configuration
              setting.  Otherwise, a domain name matches itself and its subdo-
              mains.

       <b>*</b> <i>transport</i>:<i>nexthop</i>
              The special pattern <b>*</b> represents any address (i.e. it  functions
              as  the  wild-card  pattern,  and is unique to Postfix transport
              tables).

       Note   1:   the   null   recipient   address   is    looked    up    as
       <b>$<a href="postconf.5.html#empty_address_recipient">empty_address_recipient</a></b>@<b>$<a href="postconf.5.html#myhostname">myhostname</a></b> (default: mailer-daemon@hostname).

       Note 2: <i>user@domain</i> or <i>user+extension@domain</i>  lookup  is  available  in
       Postfix 2.0 and later.

<b>RESULT FORMAT</b>
       The  lookup  result  is  of  the form <i>transport</i><b>:</b><i>nexthop</i>.  The <i>transport</i>
       field specifies a mail delivery transport such as <b>smtp</b>  or  <b>local</b>.  The
       <i>nexthop</i> field specifies where and how to deliver mail.

       The  transport  field  specifies  the name of a mail delivery transport
       (the first name of a mail delivery service entry in  the  Postfix  <a href="master.5.html"><b>mas-</b>
       <b>ter.cf</b></a> file).

       The  nexthop  field usually specifies one recipient domain or hostname.
       In the case of the Postfix SMTP/LMTP client, the nexthop field may con-
       tain  a  list  of nexthop destinations separated by comma or whitespace
       (Postfix 3.5 and later).

       The syntax of a nexthop destination is transport dependent.  With SMTP,
       specify a service on a non-default port as <i>host</i>:<i>service</i>, and disable MX
       (mail exchanger) DNS lookups with [<i>host</i>] or [<i>host</i>]:<i>port</i>. The [] form is
       required when you specify an IP address instead of a hostname.

       A  null <i>transport</i> and null <i>nexthop</i> field 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 <i>transport</i> field with a null <i>nexthop</i> field resets the nexthop
       information to the recipient domain.

       A null <i>transport</i> field with non-null <i>nexthop</i> field does not modify  the
       transport information.

<b>EXAMPLES</b>
       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 spec-
       ify a wildcard for all other destinations.

            <b>my.domain    :</b>
            <b>.my.domain   :</b>
            <b>*            <a href="smtp.8.html">smtp</a>:outbound-relay.my.domain</b>

       In order to send mail for <b>example.com</b> and its subdomains via  the  <b>uucp</b>
       transport to the UUCP host named <b>example</b>:

            <b>example.com      uucp:example</b>
            <b>.example.com     uucp:example</b>

       When  no nexthop host name is specified, the destination domain name is
       used instead. For example, the following directs  mail  for  <i>user</i>@<b>exam-</b>
       <b>ple.com</b>  via  the  <b>slow</b>  transport to a mail exchanger for <b>example.com</b>.
       The <b>slow</b> transport could be configured to  run  at  most  one  delivery
       process at a time:

            <b>example.com      slow:</b>

       When no transport is specified, Postfix uses the transport that matches
       the address domain class (see DESCRIPTION above).  The following  sends
       all  mail  for  <b>example.com</b>  and  its  subdomains to host <b>gateway.exam-</b>
       <b>ple.com</b>:

            <b>example.com      :[gateway.example.com]</b>
            <b>.example.com     :[gateway.example.com]</b>

       In the above example, the [] suppress MX lookups.  This  prevents  mail
       routing loops when your machine is primary MX host for <b>example.com</b>.

       In  the case of delivery via SMTP or LMTP, one may specify <i>host</i>:<i>service</i>
       instead of just a host:

            <b>example.com      <a href="smtp.8.html">smtp</a>:bar.example:2025</b>

       This directs mail for <i>user</i>@<b>example.com</b> to host <b>bar.example</b>  port  <b>2025</b>.
       Instead  of  a  numerical  port a symbolic name may be used. Specify []
       around the hostname if MX lookups must be disabled.

       Deliveries via SMTP or LMTP support multiple destinations  (Postfix  &gt;=
       3.5):

            <b>example.com      <a href="smtp.8.html">smtp</a>:bar.example, foo.example</b>

       This  tries  to  deliver  to  <b>bar.example</b>  before  trying to deliver to
       <b>foo.example</b>.

       The error mailer can be used to bounce mail:

            <b>.example.com     <a href="error.8.html">error</a>:mail for *.example.com is not deliverable</b>

       This causes all mail for <i>user</i>@<i>anything</i><b>.example.com</b> to be bounced.

<b>REGULAR EXPRESSION 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_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>.

       Each pattern is a regular expression that  is  applied  to  the  entire
       address  being  looked up. Thus, <i>some.domain.hierarchy</i> is not looked up
       via  its  parent  domains,  nor  is  <i>user+foo@domain</i>   looked   up   as
       <i>user@domain</i>.

       Patterns  are  applied  in the order as specified in the table, until a
       pattern is found that matches the search string.

       The <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a> server disallows regular expression substitution
       of $1 etc. in regular expression lookup tables, because that could open
       a security hole (Postfix version 2.3 and later).

<b>TCP-BASED TABLES</b>
       This section describes how the table lookups change  when  lookups  are
       directed   to  a  TCP-based  server.  For  a  description  of  the  TCP
       client/server lookup protocol, see <a href="tcp_table.5.html"><b>tcp_table</b>(5)</a>.  This feature  is  not
       available up to and including Postfix version 2.4.

       Each  lookup  operation  uses the entire recipient address once.  Thus,
       <i>some.domain.hierarchy</i> is not looked up via its parent domains,  nor  is
       <i>user+foo@domain</i> looked up as <i>user@domain</i>.

       Results are the same as with indexed file lookups.

<b>CONFIGURATION PARAMETERS</b>
       The  following  <a href="postconf.5.html"><b>main.cf</b></a>  parameters  are especially relevant.  The text
       below provides only a  parameter  summary.  See  <a href="postconf.5.html"><b>postconf</b>(5)</a>  for  more
       details including examples.

       <b><a href="postconf.5.html#empty_address_recipient">empty_address_recipient</a> (MAILER-DAEMON)</b>
              The recipient of mail addressed to the null address.

       <b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> (see 'postconf -d' output)</b>
              A  list of Postfix features where the pattern "example.com" also
              matches subdomains  of  example.com,  instead  of  requiring  an
              explicit ".example.com" pattern.

       <b><a href="postconf.5.html#transport_maps">transport_maps</a> (empty)</b>
              Optional  lookup  tables with mappings from recipient address to
              (message delivery transport, next-hop destination).

<b>SEE ALSO</b>
       <a href="trivial-rewrite.8.html">trivial-rewrite(8)</a>, rewrite and resolve addresses
       <a href="master.5.html">master(5)</a>, <a href="master.5.html">master.cf</a> file format
       <a href="postconf.5.html">postconf(5)</a>, configuration parameters
       <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager

<b>README FILES</b>
       <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a>, address rewriting guide
       <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
       <a href="FILTER_README.html">FILTER_README</a>, external content filter

<b>LICENSE</b>
       The Secure Mailer license must be distributed with this software.

<b>AUTHOR(S)</b>
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                  TRANSPORT(5)
</pre> </body> </html>