1 .\" Copyright (c) 1983, 1987 The Regents of the University of California.
2 .\" All rights reserved.
4 .\" @(#)mailaddr.7 6.5 (Berkeley) 2/14/89
6 .\" Extensively rewritten by Arnt Gulbrandsen <agulbra@troll.no>. My
7 .\" changes are placed under the same copyright as the original BSD page.
9 .\" Adjusted by Arnt Gulbrandsen <arnt@gulbrandsen.priv.no> in 2004 to
10 .\" account for changes since 1995. Route-addrs are now even less
11 .\" common, etc. Some minor wording improvements. Same copyright.
13 .\" %%%LICENSE_START(PERMISSIVE_MISC)
14 .\" Redistribution and use in source and binary forms are permitted
15 .\" provided that the above copyright notice and this paragraph are
16 .\" duplicated in all such forms and that any documentation,
17 .\" advertising materials, and other materials related to such
18 .\" distribution and use acknowledge that the software was developed
19 .\" by the University of California, Berkeley. The name of the
20 .\" University may not be used to endorse or promote products derived
21 .\" from this software without specific prior written permission.
22 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
23 .\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
24 .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
27 .TH mailaddr 7 (date) "Linux man-pages (unreleased)"
30 mailaddr \- mail addressing description
33 This manual page gives a brief introduction to SMTP mail addresses,
34 as used on the Internet.
35 These addresses are in the general format
43 where a domain is a hierarchical dot-separated list of subdomains.
44 These examples are valid forms of the same address:
48 john.doe@monet.example.com
49 John Doe <john.doe@monet.example.com>
50 john.doe@monet.example.com (John Doe)
54 The domain part ("monet.example.com") is a mail-accepting domain.
55 It can be a host and in the past it usually was, but it doesn't have to be.
56 The domain part is not case sensitive.
58 The local part ("john.doe") is often a username,
59 but its meaning is defined by the local software.
60 Sometimes it is case sensitive,
61 although that is unusual.
62 If you see a local-part that looks like garbage,
63 it is usually because of a gateway between an internal e-mail
64 system and the net, here are some examples:
68 "surname/admd=telemail/c=us/o=hp/prmd=hp"@some.where
69 USER%SOMETHING@some.where
70 machine!machine!name@some.where
75 (These are, respectively, an X.400 gateway, a gateway to an arbitrary
76 internal mail system that lacks proper internet support, an UUCP
77 gateway, and the last one is just boring username policy.)
79 The real-name part ("John Doe") can either be placed before
80 <>, or in () at the end.
81 (Strictly speaking the two aren't the same,
82 but the difference is beyond the scope of this page.)
83 The name may have to be quoted using "", for example, if it contains ".":
87 "John Q. Doe" <john.doe@monet.example.com>
91 Some mail systems let users abbreviate the domain name.
93 users at example.com may get away with "john.doe@monet" to
94 send mail to John Doe.
95 .I This behavior is deprecated.
96 Sometimes it works, but you should not depend on it.
98 In the past, sometimes one had to route a message through
99 several hosts to get it to its final destination.
100 Addresses which show these relays are termed "route-addrs".
101 These use the syntax:
105 <@hosta,@hostb:user@hostc>
109 This specifies that the message should be sent to hosta,
110 from there to hostb, and finally to hostc.
111 Many hosts disregard route-addrs and send directly to hostc.
113 Route-addrs are very unusual now.
114 They occur sometimes in old mail archives.
115 It is generally possible to ignore all but the "user@hostc"
116 part of the address to determine the actual address.
118 Every site is required to have a user or user alias designated
119 "postmaster" to which problems with the mail system may be
121 The "postmaster" address is not case sensitive.
132 .UR http://www.ietf.org\:/rfc\:/rfc5322.txt