TRANSPORT(5)                                                      TRANSPORT(5)

       transport - Postfix transport table format

       postmap /etc/postfix/transport

       postmap -q "string" /etc/postfix/transport

       postmap -q - /etc/postfix/transport <inputfile

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

       This  mapping  overrides  the  default   transport:nexthop
       selection that is built into Postfix:

       local_transport (default: local:$myhostname)
              This  is  the default for final delivery to domains
              listed with mydestination, and for [ipaddress] des-
              tinations    that    match    $inet_interfaces   or
              $proxy_interfaces. The default nexthop  destination
              is the MTA hostname.

       virtual_transport (default: virtual:)
              This  is  the default for final delivery to domains
              listed with  virtual_mailbox_domains.  The  default
              nexthop destination is the recipient domain.

       relay_transport (default: relay:)
              This  is the default for remote delivery to domains
              listed with relay_domains. In order  of  decreasing
              precedence,  the  nexthop destination is taken from
              relay_transport,   sender_dependent_relayhost_maps,
              relayhost, or from the recipient domain.

       default_transport (default: smtp:)
              This  is  the  default for remote delivery to other
              destinations.  In order of  decreasing  precedence,
              the    nexthop    destination    is    taken   from
              default_transport, sender_dependent_relayhost_maps,
              relayhost, or from the recipient domain.

       Normally,  the  transport(5)  table is specified as a text
       file that serves as input to the postmap(1) command.   The
       result,  an  indexed file in dbm or db format, is used for
       fast searching by the mail  system.  Execute  the  command
       "postmap  /etc/postfix/transport"  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 expres-
       sions, or lookups can be directed to 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".

       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 regexp: or pcre: whose
       lookup fields can match both upper and lower case.

       The input format for the postmap(1) command is as follows:

       pattern result
              When  pattern  matches  the  recipient  address  or
              domain, use the corresponding result.

       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 logi-
              cal line.

       The pattern specifies an email address, a domain name,  or
       a  domain  name  hierarchy, as described in section "TABLE

       The result is of the form transport:nexthop and  specifies
       how or where to deliver mail. This is described in section

       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:

       user+extension@domain transport:nexthop
              Deliver  mail  for  user+extension@domain   through
              transport to nexthop.

       user@domain transport:nexthop
              Deliver  mail  for user@domain through transport to

       domain transport:nexthop
              Deliver mail for domain through transport  to  nex-

       .domain transport:nexthop
              Deliver  mail  for  any subdomain of domain through
              transport to nexthop. This applies  only  when  the
              string  transport_maps  is  not  listed in the par-
              ent_domain_matches_subdomains  configuration   set-
              ting.   Otherwise, a domain name matches itself and
              its subdomains.

       * transport:nexthop
              The special pattern * 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
       $empty_address_recipient@$myhostname (default: mailer-dae-

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

       The  lookup  result is of the form transport:nexthop.  The
       transport field specifies a mail delivery  transport  such
       as  smtp  or  local. The nexthop 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 file).

       The interpretation  of  the  nexthop  field  is  transport
       dependent.  In  the  case  of SMTP, specify a service on a
       non-default port as host:service,  and  disable  MX  (mail
       exchanger)  DNS lookups with [host] or [host]:port. The []
       form is required when you specify an IP address instead of
       a hostname.

       A  null  transport  and  null nexthop result means "do not
       change": use the delivery transport and  nexthop  informa-
       tion  that  would  be used when the entire transport table
       did not exist.

       A non-null transport  field  with  a  null  nexthop  field
       resets the nexthop information to the recipient domain.

       A  null  transport  field with non-null nexthop field does
       not modify the transport information.

       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  trans-
       port  or  the  nexthop information) and specify a wildcard
       for all other destinations.

            my.domain    :
            .my.domain   :

       In order to send mail for and  its  subdomains
       via the uucp transport to the UUCP host named example:


       When  no  nexthop  host name is specified, the destination
       domain name is used instead. For  example,  the  following
       directs  mail  for via the slow transport
       to a mail exchanger for  The  slow  transport
       could be configured to run at most one delivery process at
       a time:


       When no transport is specified, Postfix uses the transport
       that  matches  the  address  domain class (see DESCRIPTION
       above).  The following sends all mail for  and
       its subdomains to host


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

       In  the  case  of delivery via SMTP, one may specify host-
       name:service instead of just a host:


       This directs mail for to host bar.example
       port 2025. Instead of a numerical port a symbolic name may
       be used. Specify [] around the hostname if MX lookups must
       be disabled.

       The error mailer can be used to bounce mail:

       error:mail for * is not deliverable

       This  causes  all mail for to be

       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 regexp_table(5) or pcre_table(5).

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

       Patterns  are applied in the order as specified in the ta-
       ble, until a pattern is  found  that  matches  the  search

       The trivial-rewrite(8) 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).

       This section describes how the table lookups  change  when
       lookups are directed to a TCP-based server. For a descrip-
       tion of the TCP client/server lookup protocol, see tcp_ta-
       ble(5).  This feature is not available up to and including
       Postfix version 2.4.

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

       Results are the same as with indexed file lookups.

       The  following parameters are especially relevant.
       The text below provides  only  a  parameter  summary.  See
       postconf(5) for more details including examples.

              The  address  that is looked up instead of the null
              sender address.

              List of Postfix features that use  domain.tld  pat-
              terns   to  match  sub.domain.tld  (as  opposed  to
              requiring .domain.tld patterns).

              List of transport lookup tables.

       trivial-rewrite(8), rewrite and resolve addresses
       master(5), file format
       postconf(5), configuration parameters
       postmap(1), Postfix lookup table manager

       ADDRESS_REWRITING_README, address rewriting guide
       DATABASE_README, Postfix lookup table overview
       FILTER_README, external content filter

       The  Secure  Mailer  license must be distributed with this

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA