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

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
       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 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
              logical 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:

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

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

       •      When "append_dot_mydomain=yes", append ".$mydomain" to addresses without ".domain".

ADDRESS EXTENSION

       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.

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 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.

TCP-BASED TABLES

       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.

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" 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".

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
              delivering mail via SMTP.

       propagate_unmatched_extensions
              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:

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

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

       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

       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

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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                                      GENERIC(5)