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  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:

       ·      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  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 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:

       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).

       The  propagate_unmatched_extensions   parameter   controls
       whether  an  unmatched  address extension (+foo) is propa‐
       gated 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- 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.

       propagate_unmatched_extensions
              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.

       owner_request_special
              Give special treatment to owner-listname and  list
              name-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
       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)