# TRANSPORT(5)                                                      TRANSPORT(5)
# 
# NAME
#        transport - Postfix transport table format
# 
# SYNOPSIS
#        postmap /etc/postfix/transport
# 
#        postmap -q "string" /etc/postfix/transport
# 
#        postmap -q - /etc/postfix/transport <inputfile
# 
# DESCRIPTION
#        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  master.cf  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 sender_depen-
#               dent_default_transport_maps,     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 regu-
#        lar-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".
# 
# CASE FOLDING
#        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.
# 
# TABLE FORMAT
#        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
#        SEARCH ORDER".
# 
#        The  result is of the form transport:nexthop and specifies
#        how or where to deliver mail. This is described in section
#        "RESULT FORMAT".
# 
# TABLE SEARCH ORDER
#        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
#               nexthop.
# 
#        domain transport:nexthop
#               Deliver  mail  for domain through transport to nex-
#               thop.
# 
#        .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-
#        mon@hostname).
# 
#        Note  2:  user@domain  or  user+extension@domain lookup is
#        available in Postfix 2.0 and later.
# 
# RESULT FORMAT
#        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 master.cf file).
# 
#        The  nexthop  field usually specifies one recipient domain
#        or hostname. In the case of the Postfix SMTP/LMTP  client,
#        the  nexthop  field may contain a list of nexthop destina-
#        tions separated by comma or whitespace  (Postfix  3.5  and
#        later).
# 
#        The  syntax  of  a nexthop destination is transport depen-
#        dent.  With 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 host-
#        name.
# 
#        A null transport and null  nexthop  field  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.
# 
# EXAMPLES
#        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   :
#             *            smtp:outbound-relay.my.domain
# 
#        In  order  to send mail for example.com and its subdomains
#        via the uucp transport to the UUCP host named example:
# 
#             example.com      uucp:example
#             .example.com     uucp:example
# 
#        When no nexthop host name is  specified,  the  destination
#        domain  name  is  used instead. For example, the following
#        directs mail for user@example.com via the  slow  transport
#        to  a  mail exchanger for example.com.  The slow transport
#        could be configured to run at most one delivery process at
#        a time:
# 
#             example.com      slow:
# 
#        When no transport is specified, Postfix uses the transport
#        that matches the address  domain  class  (see  DESCRIPTION
#        above).   The following sends all mail for example.com and
#        its subdomains to host gateway.example.com:
# 
#             example.com      :[gateway.example.com]
#             .example.com     :[gateway.example.com]
# 
#        In the above example, the [] suppress  MX  lookups.   This
#        prevents  mail  routing loops when your machine is primary
#        MX host for example.com.
# 
#        In the case of delivery via SMTP or LMTP, one may  specify
#        host:service instead of just a host:
# 
#             example.com      smtp:bar.example:2025
# 
#        This directs mail for user@example.com 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.
# 
#        Deliveries via SMTP or LMTP support multiple  destinations
#        (Postfix >= 3.5):
# 
#             example.com      smtp:bar.example, foo.example
# 
#        This  tries  to  deliver  to  bar.example before trying to
#        deliver to foo.example.
# 
#        The error mailer can be used to bounce mail:
# 
#             .example.com     error:mail for *.example.com is not deliverable
# 
#        This causes all mail for user@anything.example.com  to  be
#        bounced.
# 
# REGULAR EXPRESSION TABLES
#        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
#        string.
# 
#        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).
# 
# TCP-BASED TABLES
#        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
#        user@domain.
# 
#        Results are the same as with indexed file lookups.
# 
# CONFIGURATION PARAMETERS
#        The following main.cf parameters are especially  relevant.
#        The  text  below  provides  only  a parameter summary. See
#        postconf(5) for more details including examples.
# 
#        empty_address_recipient (MAILER-DAEMON)
#               The  recipient  of  mail  addressed  to  the   null
#               address.
# 
#        parent_domain_matches_subdomains  (see  'postconf -d' out-
#        put)
#               A list of Postfix features where the pattern "exam-
#               ple.com" also matches  subdomains  of  example.com,
#               instead  of  requiring  an  explicit ".example.com"
#               pattern.
# 
#        transport_maps (empty)
#               Optional lookup tables with mappings from recipient
#               address  to  (message  delivery transport, next-hop
#               destination).
# 
# SEE ALSO
#        trivial-rewrite(8), rewrite and resolve addresses
#        master(5), master.cf file format
#        postconf(5), configuration parameters
#        postmap(1), Postfix lookup table manager
# 
# README FILES
#        Use "postconf readme_directory" or  "postconf  html_direc-
#        tory" to locate this information.
#        ADDRESS_REWRITING_README, address rewriting guide
#        DATABASE_README, Postfix lookup table overview
#        FILTER_README, external content filter
# 
# LICENSE
#        The  Secure  Mailer  license must be distributed with this
#        software.
# 
# AUTHOR(S)
#        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)