mailaddr - mail addressing description


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


     where a domain is a hierarchical dot separated list of  sub-
     domains.  For example, the addresses

          Eric Allman <>
 (Eric Allman)

     are valid forms of the same address.

     The domain part (``'') may be the name  of
     an  internet host, or it may be a logical mail address.  The
     domain part is not case sensitive.

     The local part (``eric'') is often  a  user  name,  but  its
     meaning  is  defined  by the local software.  It can be case
     sensitive, but usually isn't.  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


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

     The real-name part (``Eric Allman'') can  either  be  placed
     first,  outside  <>, or last, inside ().  (Strictly speaking
     the two aren't the same, but the difference is  outside  the
     scope  of  this page.)  The name may have to be quoted using
     "" if it contains certain characters, most commonly ``.'':

          "Eric P. Allman" <>

     Many mail systems let users abbreviate the domain name.  For
     instance,   users   at   may  get  away  with
     ``eric@monet'' to send mail to Eric Allman. This behavior is

     Under some circumstances it may be necessary to route a mes-
     sage  through  several hosts to get it to the final destina-
     tion.  Normally this happens  automatically  and  invisibly,
     but   sometimes   not,  particularly  with  old  and  broken
     software.  Addresses which  show  these  relays  are  termed
     ``route-addrs.''  These use the syntax:


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

     Route-addrs occur  frequently  on  return  addresses,  since
     these  are generally augmented by the software at each host.
     It  is  generally   possible   to   ignore   all   but   the
     ``user@hostc''  part  of the address to determine the actual

     Every site is required to have a user or user  alias  desig-
     nated  ``postmaster'' to which problems with the mail system
     may be addressed.  The ``postmaster'' address  is  not  case

  FREQUENTLY ASKED QUESTIONS and many mirrors store a  collection  of  FAQs.
     Please  find  and use a nearby FAQ archive; there are dozens
     or  hundreds  around  the  world.   mail/inter-network-guide
     explains  how  to send mail between many different networks.
     mail/country-codes lists the top level domains (e.g.  ``no''
     is  Norway and ``ea'' is Eritrea).  mail/college-email/part*
     gives some useful tips on how to locate e-mail addresses.




     binmail(1), mail(1),  mconnect(1),  forward(5),  aliases(5),
     sendmail(8),  vrfy(8),  RFC822  (Standard  for the Format of
     Arpa Internet Text Messages).