MAILADDR(7) Linux User's Manual MAILADDR(7)
mailaddr - mail addressing description
This manual page gives a brief introduction to SMTP mail addresses, as used on the Inter-
net. These addresses are in the general format
where a domain is a hierarchical dot separated list of subdomains. For example, the
Eric Allman <firstname.lastname@example.org>
email@example.com (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:
(These are, respectively, an X.400 gateway, a gateway to an arbitrary inernal mail system
that lacks proper internet support, an UUCP gateway, and the last one is just boring user-
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 char-
acters, most commonly ``.'':
"Eric P. Allman" <firstname.lastname@example.org>
Many mail systems let users abbreviate the domain name. For instance, users at berke-
ley.edu may get away with ``eric@monet'' to send mail to Eric Allman. This behavior is
Under some circumstances it may be necessary to route a message through several hosts to
get it to the final destination. Normally this happens 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:
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.
Every site is required to have a user or user alias designated ``postmaster'' to which
problems with the mail system may be addressed. The ``postmaster'' address is not case
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.
binmail(1), mail(1), mconnect(1), forward(5), aliases(5), sendmail(8), vrfy(8), RFC822
(Standard for the Format of Arpa Internet Text Messages).
4.2 Berkeley Distribution 1995-06-24 MAILADDR(7)