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.