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                                           April 23, 2020                                       ALIASES(5)