GENERIC(5)                                                          GENERIC(5)



NAME
       generic - Postfix generic table format

SYNOPSIS
       postmap /etc/postfix/generic

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

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

DESCRIPTION
       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 localdo-
       main.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 EXAM-
       PLE 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 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 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 a mail address, replace it  by  the  corre-
              sponding 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.

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@domain address
              Replace user@domain by address. This form has the highest prece-
              dence.

       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 $proxy_interfaces.

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

RESULT ADDRESS REWRITING
       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 addresses
              without ".domain".

ADDRESS EXTENSION
       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.

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

       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 interpo-
       lated as $1, $2 and so on.

TCP-BASED TABLES
       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  con-
       stituent parts, nor is user+foo broken up into user and foo.

       Results are the same as with indexed file lookups.

EXAMPLE
       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 supports
       "+" style address extensions).

       /etc/postfix/main.cf:
           smtp_generic_maps = hash:/etc/postfix/generic

       /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".

BUGS
       The table format does not understand quoting conventions.

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.

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

       propagate_unmatched_extensions
              A list of address rewriting or forwarding mechanisms that propa-
              gate  an  address  extension  from  the  original address to the
              result.  Specify zero or more of canonical, virtual, alias, for-
              ward, include, or generic.

       Other parameters of interest:

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

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

       mydestination
              List of domains that this mail system considers local.

       myorigin
              The domain that is appended to locally-posted mail.

       owner_request_special
              Give special treatment to owner-xxx and xxx-request addresses.

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

README FILES
       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

LICENSE
       The Secure Mailer license must be distributed with this software.

HISTORY
       A genericstable feature appears in the Sendmail MTA.

       This feature is available in Postfix 2.2 and later.

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



                                                                    GENERIC(5)

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