Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!whuxl!whuxlm!akgua!gatech!seismo!brl-tgr!tgr!gds@SRI-SPAM.ARPA
From: gds@SRI-SPAM.ARPA (Greg Skinner)
Newsgroups: net.mail.headers
Subject: Re:  Quiz - Parse this From line
Message-ID: <903@brl-tgr.ARPA>
Date: Thu, 19-Dec-85 16:31:59 EST
Article-I.D.: brl-tgr.903
Posted: Thu Dec 19 16:31:59 1985
Date-Received: Sat, 21-Dec-85 06:15:07 EST
Sender: news@brl-tgr.ARPA
Lines: 42


 >> From noscvax!@MIT-MC.ARPA:hpfcla!hpcnoe!veeger!hpcnou!dat@hplabsd


Since Dave Taylor said that the message came from someone at hp-sdd,
whic is not on the ARPA Internet as far as I know, and is not
constructing 822 addresses, the From line can be read as such:

hp-sdd <-- noscvax
noscvax <-- mit-mc
mit-mc <-- hplabsd
hplabsd <-- hpcnou (though 4 hops)

The reply works in this case because MIT-MC saw fit to do source
routing, which is probably not a bad idea for mail coming from UUCP.

If the message came from someone on a smart UUCP site that did 822
header munging, or was on both ARPA and UUCP, the rightmost @ would be
favored, that's where the mess begins.

It is possible for UUCP sites to address outside of UUCP using bang
format.  For example, the above address could be folded into:

noscvax!hplabsd.arpa!....!hpcnou!dat

Note I left MIT-MC out of the picture.  MIT-MC just redistributed the
message -- it did not originate it, and has no right to be included in
reply text.  I suspect possible munging of From or From: lines.
However, if you insist on seeing MIT-MC in there,

noscvax!mc.mit.lcs.edu!hplabs.arpa!....!hpcnou!dat

Gateways/mail bridges *ought* to do the transformation between ! and 822
formats, that's what they're there for.  One of the purposes of a
gateway is to do protocol transformations on messages which is clearly
what is needed here.  No one in UUCP need know about @ or any other such
nonsense -- as long as they know the qualified names of the sites they
are sending to, they should be free to construct paths through the
gateways with legal UUCP syntax, with the gateways doing the appropriate
transformations.

--gregbo