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

4.2 Berkeley Distribution                          2023-10-31                                        mailaddr(7)