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.edu
Eric Allman <ericmonet.edu>
ericmonet.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 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%SOMETHINGsome.where machine!machine!namesome.where
I2461572some.where
(These are, respectively, an X.400 gateway, a gateway to an arbitrary
inernal mail system that lacks proper internet support, an UUCP gate-
way, and the last one is just boring username policy.)
The real-name part (''Eric Allman'') can either be placed first, out-
side <>, 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" <ericmonet.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 destination. Normally this hap-
pens 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:
<@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 gen-
erally augmented by the software at each host. It is generally possi-
ble to ignore all but the ''user@hostc'' part of the address to deter-
mine the actual sender.
Postmaster.
Every site is required to have a user or user alias designated ''post-
master'' to which problems with the mail system may be addressed. The
''postmaster'' address is not case sensitive.
FREQUENTLYASKEDQUESTIONS
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
SEEALSO
binmail(1), mail(1), mconnect(1), forward(5), aliases(5), sendmail(8),
vrfy(8), RFC822 (Standard for the Format of Arpa Internet Text Mes-
sages).
4.2 Berkeley Distribution 1995-06-24 MAILADDR(7)
Take our 
