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
user@domain
where a domain is a hierarchical dot-separated list of subdomains. These examples are valid forms of the same address:
eric@monet.berkeley.edu
Eric Allman <eric@monet.berkeley.edu>
eric@monet.berkeley.edu (Eric Allman)
The domain part ("monet.berkeley.edu") 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 ("eric") 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 ("Eric Allman") 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 ".":
"Eric P. Allman" <eric@monet.berkeley.edu>
Many mail systems let users abbreviate the domain name. For instance, users at berkeley.edu may get away with "eric@monet" to send mail to Eric Allman. This behavior is deprecated. Sometimes it works, but you should not depend on it.
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.
binmail(1), mail(1), mconnect(1), aliases(5), forward(5), sendmail(8), vrfy(8)
RFC 2822 (Internet Message Format)
This page is part of release 4.07 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/.
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Copyright (c) 1983, 1987 The Regents of the University of California. All rights reserved. (#)mailaddr.7 6.5 (Berkeley) 2/14/89 Extensively rewritten by Arnt Gulbrandsen <agulbratroll.no>. My changes are placed under the same copyright as the original BSD page. Adjusted by Arnt Gulbrandsen <arntgulbrandsen.priv.no> in 2004 to account for changes since 1995. Route-addrs are now even less common, etc. Some minor wording improvements. Same copyright. %%%LICENSE_START(PERMISSIVE_MISC) Redistribution and use in source and binary forms are permitted provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation, advertising materials, and other materials related to such distribution and use acknowledge that the software was developed by the University of California, Berkeley. The name of the University may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. %%%LICENSE_END |