NAME

       mailaddr - mail addressing description

DESCRIPTION

       This  manual  page  gives  a  brief  introduction to SMTP mail addresses, as used on the Internet.  These
       addresses are in the general format

            user@domain

       where a domain is a hierarchical dot-separated list of subdomains.  These examples are valid forms of the
       same address:

            john.doe@monet.example.com
            John Doe <john.doe@monet.example.com>
            john.doe@monet.example.com (John Doe)

       The  domain  part  ("monet.example.com") is a mail-accepting domain.  It can be a host and in the past it
       usually was, but it doesn't have to be.  The domain part is not case sensitive.

       The local part ("john.doe") is often a username, but its  meaning  is  defined  by  the  local  software.
       Sometimes  it  is  case  sensitive,  although  that  is unusual.  If you see a local-part that looks like
       garbage, it is usually because of a gateway between an internal e-mail system and the net, here are  some
       examples:

            "surname/admd=telemail/c=us/o=hp/prmd=hp"@some.where
            USER%SOMETHING@some.where
            machine!machine!name@some.where
            I2461572@some.where

       (These  are,  respectively,  an  X.400 gateway, a gateway to an arbitrary internal mail system that lacks
       proper internet support, an UUCP gateway, and the last one is just boring username policy.)

       The real-name part ("John Doe") can either be placed before <>, or in () at the end.  (Strictly  speaking
       the  two  aren't the same, but the difference is beyond the scope of this page.)  The name may have to be
       quoted using "", for example, if it contains ".":

            "John Q. Doe" <john.doe@monet.example.com>

   Abbreviation
       Some mail systems let users abbreviate the domain name.  For instance, users at example.com may get  away
       with  "john.doe@monet"  to  send mail to John Doe.  This behavior is deprecated.  Sometimes it works, but
       you should not depend on it.

   Route-addrs
       In the past, sometimes one had to route  a  message  through  several  hosts  to  get  it  to  its  final
       destination.  Addresses which show these relays are termed "route-addrs".  These use the syntax:

            <@hosta,@hostb:user@hostc>

       This specifies that the message should be sent to hosta, from there to hostb, and finally to hostc.  Many
       hosts disregard route-addrs and send directly to hostc.

       Route-addrs are very unusual now.  They occur sometimes in old mail archives.  It is  generally  possible
       to ignore all but the "user@hostc" part of the address to determine the actual address.

   Postmaster
       Every  site  is  required to have a user or user alias designated "postmaster" to which problems with the
       mail system may be addressed.  The "postmaster" address is not case sensitive.

FILES

       /etc/aliases
       ~/.forward

SEE ALSO

       mail(1), aliases(5), forward(5), sendmail(8)

       IETF RFC 5322 ⟨http://www.ietf.org/rfc/rfc5322.txt⟩

COLOPHON

       This page is part of release 4.15 of  the  Linux  man-pages  project.   A  description  of  the  project,
       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       https://www.kernel.org/doc/man-pages/.