aliases(5) — Linux manual page


ALIASES(5)                 BSD File Formats Manual                ALIASES(5)

NAME         top

     aliases — aliases file for smtpd

DESCRIPTION         top

     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.

             Append messages to file, specified by its absolute pathname.

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

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

             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
    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 dig‐
             its, starting 4XX (TempFail) or 5XX (PermFail).  The message
             must be present and can be freely chosen.

FILES         top

     /etc/mail/aliases     Default aliases file.

SEE ALSO         top

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

HISTORY         top

     The aliases file format appeared in 4.0BSD.

COLOPHON         top

     This page is part of the OpenSMTPD (a FREE implementation of the
     server-side SMTP protocol) project.  Information about the project can
     be found at  If you have a bug report for
     this manual page, see ⟨⟩.
     This page was obtained from the project's upstream Git repository
     ⟨⟩ on 2020-11-01.  (At that
     time, the date of the most recent commit that was found in the reposi‐
     tory was 2020-07-27.)  If you discover any rendering problems in this
     HTML version of the page, or you believe there is a better or more up-
     to-date source for the page, or you have corrections or improvements to
     the information in this COLOPHON (which is not part of the original
     manual page), send a mail to

BSD                            April 23, 2020                            BSD

Pages that refer to this page: endaliasent(3)getaliasbyname(3)getaliasbyname_r(3)getaliasent(3)getaliasent_r(3)setaliasent(3)mailaddr(7)