ALIASES(5)                                                          ALIASES(5)

       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.

       The input and output file formats are expected to be  com-
       patible  with  Sendmail  version 8, and are expected to be
       suitable for the use as NIS maps.

       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:

       o      An alias definition has the form

                   name: value1, value2, ...

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

       o      A logical line starts with non-whitespace  text.  A
              line  that starts with whitespace continues a logi-
              cal 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 insensi-

       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 undeliv-
       ered 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  lim-
              ited  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  simu-
              late  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 local-
       part  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  propa-
       gated to the result of table lookup.

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

       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

              Restrict  the  usage  of  mail delivery to external

              When delivering to an alias that has an owner- com-
              panion  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 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.

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

              Delimiter that separates  recipients  from  address

       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

       DATABASE_README, Postfix lookup table overview

       The Secure Mailer license must be  distributed  with  this

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA