Provided by: postfix_3.1.0-3ubuntu0.4_amd64 bug


       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 expressions, 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


       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 logical 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 $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:

       •      When the result has the form @otherdomain, the result  becomes  the  same  user  in

       •      When "append_at_myorigin=yes", append "@$myorigin" to addresses without "@domain".

       •      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 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 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 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  description  of  the  TCP  client/server  lookup protocol, see
       tcp_table(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" 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 -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 delivering mail via SMTP.

              A list of address rewriting or forwarding  mechanisms  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 Postfix when this parameter changes.

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

              List of domains that this mail system considers local.

              The domain that is appended to locally-posted mail.

              Give special treatment to owner-xxx and xxx-request addresses.


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


       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       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