GENERIC(5)                    File Formats Manual                   GENERIC(5)


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 a TCP-based server. In those cases, 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, 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
              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:

       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".

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
       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
       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 (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
              translation 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
              listname-request address localparts when the recipient_delimiter
              is set to "-".

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)