MAILADDR(7) COMMAND REFERENCE MAILADDR(7)
NAME
mailaddr - mail addressing description
DESCRIPTION
Mail addresses are based on the ARPANET protocol listed at
the end of this manual page. These addresses are in the
general format
user@domain
where a domain is a hierarchical dot separated list of
subdomains. For example, the address
eric@monet.Berkeley.ARPA
is normally interpreted from right to left: the message
should go to the ARPA name tables (which do not correspond
exactly to the physical ARPANET), then to the Berkeley
gateway, after which it should go to the local host monet.
When the message reaches monet it is delivered to the user
eric.
Unlike some other forms of addressing, this does not imply
any routing. Thus, although this address is specified as an
ARPAaddress, it might travel by an alternate route if that
was more convenient or efficient. For example, at Berkeley
the associated message would probably go directly to monet
over the Ethernet rather than going via the Berkeley ARPANET
gateway.
Abbreviation. Under certain circumstances it may not be
necessary to type the entire domain name. In general
anything following the first dot may be omitted if it is the
same as the domain from which you are sending the message.
For example, a user on calder.Berkeley.ARPA could send to
eric@monet without adding the .Berkeley.ARPA since it is the
same on both sending and receiving hosts.
Certain other abbreviations may be permitted as special
cases. For example, at Berkeley ARPANET hosts can be
referenced without adding the .ARPA as long as their names
do not conflict with a local hostname.
Compatibility. Certain old address formats are converted to
the new format to provide compatibility with the previous
mail system. In particular,
host:user
is converted to
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MAILADDR(7) COMMAND REFERENCE MAILADDR(7)
user@host
to be consistent with the rcp(1n) command.
Also, the syntax:
host!user
is converted to:
user@host.UUCP
This is normally converted back to the ``host!user'' form
before being sent on for compatibility with older UUCP
hosts.
The current implementation is not able to route messages
automatically through the UUCP network. Until that time you
must explicitly tell the mail system which hosts to send
your message through to get to your final destination.
Case Distinctions. Domain names (i.e., anything after the
``@'' sign) may be given in any mixture of upper and lower
case with the exception of UUCP hostnames. Most hosts
accept any mixture of case in user names, with the notable
exception of MULTICS sites.
Differences with ARPA Protocols. Although the UTek
addressing scheme is based on the ARPA mail addressing
protocols, there are some significant differences.
At the time of this writing the only ``top level'' domain
defined by ARPA is the .ARPA domain itself. This is further
restricted to having only one level of host specifier. That
is, the only addresses that ARPA accepts at this time must
be in the format user@host.ARPA (where host is one word).
In particular, addresses such as:
eric@monet.Berkeley.ARPA
are not currently legal under the ARPA protocols. For this
reason, these addresses are converted to a different format
on output to the ARPANET, typically:
eric%monet@Berkeley.ARPA
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 routing is done automatically,
but sometimes it is desirable to route the message manually.
An address that shows these relays are termed ``route-
addrs.'' These use the syntax:
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MAILADDR(7) COMMAND REFERENCE MAILADDR(7)
<@hosta,@hostb:user@hostc>
This specifies that the message should be sent to hosta,
from there to hostb, and finally to hostc. This path is
forced even if there is a more efficient path 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@host
part of the address to determine the actual sender.
Postmaster. Every site is required to have a user or user
alias designated ``postmaster'' to which problems with the
mail system may be addressed.
CSNET. Messages to CSNET sites can be sent to
``user.host@UDel-Relay''.
BERKELEY
The following comments apply only to the Berkeley
environment.
Hostnames. Many of the old familiar hostnames are being
phased out. In particular, single character names as used
in Berknet are incompatible with the larger world of which
Berkeley is now a member. For this reason the following
names are being phased out. You should notify any
correspondents of your new address as soon as possible.
OLD NEW
j ingvax ucbingres
p ucbcad
r arpavax ucbarpa
v csvax ucbernie
n ucbkim
y ucbcory
The old addresses will be rejected as unknown hosts sometime
in the near future.
What's My Address? If you are on a local machine, say monet,
your address is
yourname@monet.Berkeley.ARPA
However, since most of the world does not have the new
software in place yet, you will have to give correspondents
slightly different addresses. From the ARPANET, your
address would be:
yourname%monet@Berkeley.ARPA
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MAILADDR(7) COMMAND REFERENCE MAILADDR(7)
From UUCP, your address would be:
ucbvax!yourname%monet
Computer Center. The Berkeley Computer Center is in a
subdomain of Berkeley. Messages to the computer center
should be addressed to:
user%host.CC@Berkeley.ARPA
The alternate syntax:
user@host.CC
may be used if the message is sent from inside Berkeley.
For the time being Computer Center hosts are known within
the Berkeley domain, i.e., the ``.CC'' is optional.
However, it is likely that this situation will change with
time as both the Computer Science department and the
Computer Center grow.
Bitnet. Hosts on bitnet may be accessed using:
user@host.BITNET
SEE ALSO
mail(1), sendmail(8mh).
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