Section (7) mailaddr
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 subdomains. These examples are valid forms of the same address:
John Doe <[email protected]>
[email protected] (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_zsingle_quotesz_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:
(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_zsingle_quotesz_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 <[email protected]>
Some mail systems let users abbreviate the domain name. For instance, users at example.com may get away with [email protected] to send mail to John Doe. 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:
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 [email protected] part of the address to determine the actual address.
mail(1), aliases(5), forward(5), sendmail(8)
This page is part of release 4.16 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
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.
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provided that the above copyright notice and this paragraph are
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THIS SOFTWARE IS PROVIDED ``AS IS_zsingle_quotesz__zsingle_quotesz_ AND WITHOUT ANY EXPRESS OR
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