NAME

       aliases — aliases file for smtpd

DESCRIPTION

       This  manual  page  describes  the  format  of  the  aliases file, as used by smtpd(8).  An alias, in its
       simplest form, is used to assign an arbitrary name to an email address or a  group  of  email  addresses.
       This  provides  a convenient way to send mail.  For example an alias could refer to all users of a group:
       email to that alias would be sent to all members of the group.  Much more complex aliases can be  defined
       however:  an  alias can refer to other aliases, be used to send mail to a file instead of another person,
       or to execute various commands.

       Within the file, ‘#’ is a comment delimiter; anything placed after it is discarded.  The file consists of
       key/value mappings of the form:

             key: value1, value2, value3, ...

       key is always folded to lowercase before alias lookups to ensure that there can be no ambiguity.  The key
       is expanded to the corresponding values, which consist of one or more of the following:

       user    A user on the host machine.  The user must have a valid entry in the passwd(5) database file.

       /path/to/file
               Append messages to file, specified by its absolute pathname.

       |command
               Pipe the message to command on its standard input.  The command is run under  the  privileges  of
               the daemon's unprivileged account.

       :include:/path/to/file
               Include  any  definitions  in file as alias entries.  The format of the file is identical to this
               one.

       user-part@domain-part
               An email address in RFC 5322 format.  If an address extension is appended to the user-part, it is
               first  compared  for  an  exact  match.   It  is  then  stripped  so  that  an  address  such  as
               user+ext@example.com will only use the part that precedes ‘+’ as a key.

       error:code message
               A  status  code and message to return.  The code must be 3 digits, starting 4XX (TempFail) or 5XX
               (PermFail).  The message must be present and can be freely chosen.

FILES

       /etc/aliases     Default aliases file.

SEE ALSO

       smtpd.conf(5), makemap(8), newaliases(8), smtpd(8)

HISTORY

       The aliases file format appeared in 4.0BSD.

Debian                                          February 13, 2021                                     ALIASES(5)