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" 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 expres-
           sions, 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 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 2.4.

           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.

    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)