Computer Science
MAILADDR(7) Linux User's Manual MAILADDR(7)
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. For example, the addresses
eric@monet.berkeley.edu
Eric Allman <eric@monet.berkeley.edu>
eric@monet.berkeley.edu (Eric Allman)
are valid forms of the same address.
The domain part (``monet.berkeley.edu'') 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 gate-
way 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 inernal mail system that lacks proper inter-
net 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" <eric@monet.berkeley.edu>
Abbreviation.
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.
Route-addrs.
Under some circumstances it may be necessary to route a
message through several hosts to get it to the final des-
tination. Normally this happens automatically and invisi-
bly, but sometimes not, particularly with old and broken
software. 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. 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
sender.
Postmaster.
Every site is required to have a user or user alias desig-
nated ``postmaster'' to which problems with the mail sys-
tem may be addressed. The ``postmaster'' address is not
case sensitive.
FREQUENTLY ASKED QUESTIONS
rtfm.mit.edu 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.
FILES
/etc/aliases
~/.forward
SEE ALSO
binmail(1), mail(1), mconnect(1), forward(5), aliases(5),
sendmail(8), vrfy(8), RFC822 (Standard for the Format of
Arpa Internet Text Messages).
linux June 24, 1995 1
Back to the index