GENERICS(5)                                           GENERICS(5)

       generics - Postfix generics table format

       postmap /etc/postfix/generics

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

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

       The  optional  generics(5) table specifies an address map-
       ping 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 generics(5) table on a system
       that  does  not have a valid Internet domain name and that
       uses something like localdomain.local instead.  The gener-
       ics(5)  table is then used by the smtp(8) client to trans-
       form  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  generics(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  generics(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/generics"  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".

       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.

       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

       @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 recip-
       ient delimiter (e.g., user+foo@domain), the  lookup  order
       becomes: user+foo@domain, user@domain, user+foo, user, and

       The  propagate_unmatched_extensions   parameter   controls
       whether  an  unmatched  address extension (+foo) is propa-
       gated to the result of table lookup.

       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

       Patterns  are  applied  in  the  order as specified in the
       table, until a pattern is found that  matches  the  search

       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.

       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_table(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.

       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_generics_maps = hash:/etc/postfix/generics

               his@localdomain.local   hisaccount@hisisp.example
               her@localdomain.local   heraccount@herisp.example
               @localdomain.local      hisaccount+local@hisisp.example

       Execute the command "postmap /etc/postfix/generics"  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".

       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.

              Address  mapping  lookup  table  for  envelope  and
              header  sender and recipient addresses while deliv-
              ering mail via SMTP.

              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 generics.

       Other parameters of interest:

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

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

              List of domains that  this  mail  system  considers

              The domain that is appended to locally-posted mail.

              Give special treatment to owner-xxx and xxx-request

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

       DATABASE_README, Postfix lookup table overview
       ADDRESS_REWRITING_README, address rewriting guide

       The Secure Mailer license must be  distributed  with  this

       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