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 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 a TCP-based server. In those cases, the lookups are done in
       a slightly different way as described below under  "REGULAR  EXPRESSION

       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.

       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.

       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-

       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.

       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".

       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

       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.

       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
       available in Postfix 2.5 and later.

       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.

       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).

           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

       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.

       smtp_generic_maps (empty)
              Optional lookup tables that perform  address  rewriting  in  the
              Postfix  SMTP  client,  typically  to  transform a locally valid
              address into a globally valid address when sending  mail  across
              the Internet.

       propagate_unmatched_extensions (canonical, virtual)
              What  address  lookup  tables copy an address extension from the
              lookup key to the lookup result.

       Other parameters of interest:

       inet_interfaces (all)
              The local network interface  addresses  that  this  mail  system
              receives mail on.

       proxy_interfaces (empty)
              The  remote  network  interface  addresses that this mail system
              receives mail on by way of a proxy or network  address  transla-
              tion unit.

       mydestination ($myhostname, localhost.$mydomain, localhost)
              The  list of domains that are delivered via the $local_transport
              mail delivery transport.

       myorigin ($myhostname)
              The domain name that locally-posted mail appears to  come  from,
              and that locally posted mail is delivered to.

       owner_request_special (yes)
              Enable  special  treatment  for  owner-listname  entries  in the
              aliases(5)  file,  and  don't  split  owner-listname  and  list-
              name-request  address localparts when the recipient_delimiter is
              set to "-".

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

       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 software.

       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