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  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"  in  order  to rebuild the
           indexed file after changing the 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 expres-
           sions, or lookups can be directed to TCP-based server.  In
           that  case,  the  lookups are done in a slightly different
           way as described below under "REGULAR  EXPRESSION  TABLES"
           and "TCP-BASED TABLES".

    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 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.

    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 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
                  $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 recip-
           ient 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 propa-
           gated 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  broken 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 ta-
           ble, 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.

    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 2.2.

           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.

    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"  when-
           ever  the table is changed.  Instead of hash, some systems
           use dbm database files. To find out what tables your  sys-
           tem 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 deliv-
                  ering mail via SMTP.

           propagate_unmatched_extensions
                  A list of address rewriting  or  forwarding  mecha-
                  nisms  that propagate an address extension from the
                  original address to the result.   Specify  zero  or
                  more   of   canonical,   virtual,  alias,  forward,
                  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 Post-
                  fix when this parameter changes.

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

           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

                                                                        GENERIC(5)