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

       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".

       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 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  ta-
       ble,  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_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.

       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" 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 generic.

       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

       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

       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