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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!plus5!hokey
From: hokey@plus5.UUCP (Hokey)
Newsgroups: net.mail.headers
Subject: Re: Why "From cbosgd!cbosgd.ATT.UUCP!chris" isn't stupid
Message-ID: <771@plus5.UUCP>
Date: Wed, 19-Jun-85 17:06:55 EDT
Article-I.D.: plus5.771
Posted: Wed Jun 19 17:06:55 1985
Date-Received: Thu, 20-Jun-85 12:05:53 EDT
References: <1214@cbosgd.UUCP> <515@down.FUN> <766@plus5.UUCP> <1269@houxm.UUCP>
Reply-To: hokey@plus5.UUCP (Hokey)
Organization: Plus Five Computer Services, St. Louis, MO
Lines: 27

The primary issue is sending mail.  It is desireable to minimize typing.
It is desireable to unambiguously specify the *address* of the recipient.

If cbosgd is sending mail to a "dumb" site, sufficient *routing* information
must be added to permit replies to be delivered (via dumb mailers).  As
more and more machines hit the net, we have a problem with name collisions.
One solution to this problem is domains.  The domain form is "rooted",
which makes it possible to have duplicate machine names without fear of
causing mailers to choke.  The bang-format names can only be used to provide
duplicate names under specific semantic circumstances.  The domain scheme
provides these conditions syntactically.

It just so happens that the domain name of cbosgd happens to be
cbosgd.att.uucp.  People can look at this, and "know" that site names exist
below the att.uucp, but this is a *semantic* decision!  The initial cbosgd!
gets prepended specifically to provide backward-compatability with dumb
mailers.

If your mailer does not need this information, there are two solutions: tell
cbosgd not to automatically do this for you, or tell your sendmail to
strip it off.  Both capabilities are useful.

In either of the latter two cases, make sure your mailer really is smart
enough to handle the consequences!
-- 
Hokey           ..ihnp4!plus5!hokey
		  314-725-9492