GENERIC(5)                                             GENERIC(5)

          generic - Postfix generic table format

          postmap /etc/postfix/generic

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

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

          The optional generic(5) table specifies an  address  mapping
          that applies when mail is delivered. This is the opposite of
          canonical(5) mapping, which applies when mail is received.

          Typically, one would use the generic(5) table  on  a  system
          that  does  not  have  a valid Internet domain name and that
          uses  something   like   localdomain.local   instead.    The
          generic(5)  table  is  then  used  by  the smtp(8) client to
          transform local mail  addresses  into  valid  Internet  mail
          addresses when mail has to be sent across the Internet.  See
          the EXAMPLE section at the end of this document.

          The generic(5) mapping affects both message header addresses
          (i.e.  addresses  that  appear  inside messages) and message
          envelope addresses (for example, the addresses that are used
          in SMTP protocol commands).

          Normally, the generic(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/generic"  to  rebuild  an  indexed  file  after
          changing the corresponding text file.

          When the table is provided via other means such as NIS, LDAP
          or  SQL,  the  same lookups are done as for ordinary indexed

          Alternatively,   the   table   can   be   provided   as    a
          regular-expression  map  where patterns are given as regular
          expressions, 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

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     GENERIC(5)                                             GENERIC(5)

          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 a mail address, replace it by  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 logical line.

          With lookups from indexed files such as DB or DBM,  or  from
          networked  tables such as NIS, LDAP or SQL, each user@domain
          query produces a sequence of  query  patterns  as  described

          Each query pattern is sent to each  specified  lookup  table
          before  trying  the  next  query  pattern,  until a match is

          user@domain address
               Replace user@domain  by  address.  This  form  has  the
               highest precedence.

          user address
               Replace user@site by address  when  site  is  equal  to
               $myorigin,  when  site  is listed in $mydestination, or
               when   it   is   listed    in    $inet_interfaces    or

          @domain address
               Replace other addresses in  domain  by  address.   This
               form has the lowest precedence.

          The lookup result is subject to address rewriting:

          +o    When the result has the form @otherdomain,  the  result
               becomes the same user in otherdomain.

          +o    When "append_at_myorigin=yes", append  "@$myorigin"  to
               addresses without "@domain".

          +o    When "append_dot_mydomain=yes", append ".$mydomain"  to

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     GENERIC(5)                                             GENERIC(5)

               addresses without ".domain".

          When  a  mail  address  localpart  contains   the   optional
          recipient  delimiter  (e.g.,  user+foo@domain),  the  lookup
          order becomes: user+foo@domain, user@domain, user+foo, user,
          and @domain.

          The   propagate_unmatched_extensions   parameter    controls
          whether  an unmatched address extension (+foo) is propagated
          to the result of table lookup.

          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,  user@domain mail
          addresses are not broken up  into  their  user  and  @domain
          constituent  parts,  nor is user+foo broken up into user and

          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 indexed file lookups, with  the
          additional  feature  that  parenthesized substrings from the
          pattern can be interpolated as $1, $2 and so on.

          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
          tcp_table(5).   This  feature  is  not  available  up to and
          including Postfix version 2.4.

          Each lookup operation uses the entire address  once.   Thus,
          user@domain mail addresses are not broken up into their user
          and @domain constituent parts, nor  is  user+foo  broken  up
          into user and foo.

          Results are the same as with indexed file lookups.

          The following shows a generic mapping with an indexed  file.
          When  mail  is sent to a remote host via SMTP, this replaces
          his@localdomain.local by  his  ISP  mail  address,  replaces
          her@localdomain.local  by her ISP mail address, and replaces
          other local addresses by his ISP account,  with  an  address
          extension  of  +local  (this  example  assumes  that the ISP

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     GENERIC(5)                                             GENERIC(5)

          supports "+" style address extensions).

              smtp_generic_maps = hash:/etc/postfix/generic

              his@localdomain.local   hisaccount@hisisp.example
              her@localdomain.local   heraccount@herisp.example
              @localdomain.local      hisaccount+local@hisisp.example

          Execute the command "postmap /etc/postfix/generic"  whenever
          the table is changed.  Instead of hash, some systems use dbm
          database files. To find out what tables your system supports
          use the command "postconf -m".

          The table format does not understand quoting conventions.

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

               Address mapping lookup table for  envelope  and  header
               sender  and  recipient  addresses while delivering mail
               via SMTP.

               A list of address rewriting  or  forwarding  mechanisms
               that  propagate  an address extension from the original
               address  to  the  result.   Specify  zero  or  more  of
               canonical,   virtual,   alias,   forward,  include,  or

          Other parameters of interest:

               The  network  interface  addresses  that  this   system
               receives  mail  on.  You need to stop and start Postfix
               when this parameter changes.

               Other interfaces that this machine receives mail on  by
               way of a proxy agent or network address translator.

               List of domains that this mail system considers local.

               The domain that is appended to locally-posted mail.

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     GENERIC(5)                                             GENERIC(5)

               Give special treatment  to  owner-xxx  and  xxx-request

          postmap(1), Postfix lookup table manager
          postconf(5), configuration parameters
          smtp(8), Postfix SMTP client

          Use "postconf readme_directory" or "postconf html_directory"
          to locate this information.
          ADDRESS_REWRITING_README, address rewriting guide
          DATABASE_README, Postfix lookup table overview
          STANDARD_CONFIGURATION_README, configuration examples

          The Secure Mailer license  must  be  distributed  with  this

          A genericstable feature appears in the Sendmail MTA.

          This feature is available in Postfix 2.2 and later.

          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

     Page 5                       Plan 9             (printed 5/26/22)