Postfix manual - generic(5)

    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,  each  user@domain  query  produces  a
           sequence of query patterns as described below.

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

           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
           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

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

                                                                        GENERIC(5)