ALIASES(5)                                                          ALIASES(5)



NAME
       aliases - Postfix local alias database format

SYNOPSIS
       newaliases

DESCRIPTION
       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 compatible 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 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 mes-
       sage.  This is typically used to direct delivery errors  to  the  main-
       tainer  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:

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

       /file/name
              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.

       |command
              Mail  is piped into command. Commands that contain special char-
              acters, 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  imple-
              ment an expensive black hole.

       :include:/file/name
              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_com-
              mands and allow_mail_to_files configuration parameters.

ADDRESS EXTENSION
       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.

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

SECURITY
       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.

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.

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

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

       allow_mail_to_commands
              Restrict the usage of mail delivery to external command.

       allow_mail_to_files
              Restrict the usage of mail delivery to external file.

       expand_owner_alias
              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.

       propagate_unmatched_extensions
              A list of address rewriting or forwarding mechanisms that propa-
              gate an address extension  from  the  original  address  to  the
              result.  Specify zero or more of canonical, virtual, alias, for-
              ward, include, or generic.

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

       recipient_delimiter
              Delimiter that separates recipients from address extensions.

       Available in Postfix version 2.3 and later:

       frozen_delivered_to
              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.

STANDARDS
       RFC 822 (ARPA Internet Text Messages)

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

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

LICENSE
       The Secure Mailer license must be distributed with this software.

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



                                                                    ALIASES(5)
