    ALIASES(5)                                             ALIASES(5)

    NAME
           aliases - format of the Postfix alias database

    SYNOPSIS
           newaliases

    DESCRIPTION
           The  aliases  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  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 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-
           tive.

           In addition, when an alias exists for owner-name, delivery
           diagnostics  are  directed  to that address, instead of to
           the originator.  This is typically used to direct delivery
           errors  to the owner 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 lim-
                  ited 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 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.

           :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_commands  and
                  allow_mail_to_files configuration parameters.

    ADDRESS EXTENSION
           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).

    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- 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.

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

           recipient_delimiter
                  Delimiter that separates  recipients  from  address
                  extensions.

    BUGS
           Regular  expression  alias  lookup tables are allowed, but
           substitution of $1 etc. is forbidden  because  that  would
           open a security loophole.

    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
           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)