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


       aliases - Postfix local alias database format




       The  aliases(5)  table  provides  a  system-wide  mechanism  to  redirect  mail  for local
       recipients. The redirections are processed by the Postfix local(8) delivery agent.

       Normally, the aliases(5) table is specified as a text file that serves  as  input  to  the
       postalias(1)  command.  The  result, an indexed file in dbm or db format, is used for fast
       lookup by the mail system. Execute the command newaliases in order to rebuild the  indexed
       file after changing the Postfix alias database.

       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. In this case, the lookups are done in a slightly different
       way as described below under "REGULAR EXPRESSION TABLES".

       Users can control delivery of their own mail by setting up .forward files  in  their  home
       directory.   Lines  in per-user .forward files have the same syntax as the right-hand side
       of aliases(5) entries.

       The format of the alias database input file is as follows:

       •      An alias definition has the form

                   name: value1, value2, ...

       •      Empty lines and whitespace-only  lines  are  ignored,  as  are  lines  whose  first
              non-whitespace character is a `#'.

       •      A  logical line starts with non-whitespace text. A line that starts with whitespace
              continues a logical line.

       The name is a local address (no domain part).  Use double quotes when  the  name  contains
       any  special  characters  such  as  whitespace,  `#',  `:',  or `@'. The name is folded to
       lowercase, in order to make database lookups case insensitive.

       In addition, when an alias exists for owner-name, delivery  diagnostics  are  directed  to
       that  address,  instead  of  to  the originator of the message.  This is typically used to
       direct delivery errors to the maintainer of a mailing list, who is in a better position to
       deal with mailing list delivery problems than the originator of the undelivered mail.

       The value contains one or more of the following:

              Mail is forwarded to address, which is compatible with the RFC 822 standard.

              Mail  is  appended  to  /file/name.  See  local(8) for details of delivery to file.
              Delivery is not limited to regular files.  For  example,  to  dispose  of  unwanted
              mail, deflect it to /dev/null.

              Mail  is  piped  into  command.  Commands  that contain special characters, such as
              whitespace, should be enclosed between double quotes. See local(8) for  details  of
              delivery to command.

              When  the  command  fails, a limited amount of command output is mailed back to the
              sender.  The file /usr/include/sysexits.h defines the expected exit  status  codes.
              For  example,  use  "|exit 67" to simulate a "user unknown" error, and "|exit 0" to
              implement an expensive black hole.

              Mail is sent to the destinations listed in the  named  file.   Lines  in  :include:
              files have the same syntax as the right-hand side of alias entries.

              A  destination  can  be  any  destination  that  is  described in this manual page.
              However, delivery to "|command" and /file/name is disallowed by default. To enable,
              edit the allow_mail_to_commands and allow_mail_to_files configuration parameters.


       When  alias  database  search  fails,  and  the  recipient localpart contains the optional
       recipient delimiter (e.g., user+foo), the search is repeated for  the  unextended  address
       (e.g., user).

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


       The local(8) delivery agent always folds the search string to  lowercase  before  database


       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).  NOTE:  these  formats  do not use ":" at the end of a

       Each regular expression is applied to the entire search  string.  Thus,  a  search  string
       user+foo is not broken up into user and foo.

       Regular  expressions  are  applied in the order as specified in the table, until a regular
       expression is found that matches the search string.

       Lookup results are the same as with indexed file lookups.  For security reasons  there  is
       no support for $1, $2 etc. substring interpolation.


       The  local(8)  delivery  agent  disallows  regular  expression  substitution of $1 etc. in
       alias_maps, because that would open a security hole.

       The local(8) delivery agent will silently ignore requests to use  the  proxymap(8)  server
       within  alias_maps.  Instead it will open the table directly.  Before Postfix version 2.2,
       the local(8) delivery agent will terminate with a fatal error.


       The following parameters are especially relevant.  The text below provides only  a
       parameter summary. See postconf(5) for more details including examples.

              List of alias databases that are updated by the newaliases(1) command.

              List of alias databases queried by the local(8) delivery agent.

              Restrict the usage of mail delivery to external command.

              Restrict the usage of mail delivery to external file.

              When  delivering  to  an alias that has an owner- companion alias, set the envelope
              sender address to the right-hand side of the owner  alias,  instead  using  of  the
              left-hand side address.

              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.

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

              Delimiter that separates recipients from address extensions.

       Available in Postfix version 2.3 and later:

              Update    the    local(8)    delivery    agent's    Delivered-To:    address   (see
              prepend_delivered_header) only once, at the start of a delivery; do not update  the
              Delivered-To: address while expanding aliases or .forward files.


       RFC 822 (ARPA Internet Text Messages)


       local(8), local delivery agent
       newaliases(1), create/update alias database
       postalias(1), create/update alias database
       postconf(5), configuration parameters


       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       DATABASE_README, Postfix lookup table overview


       The Secure Mailer license must be distributed with this software.


       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