Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version VT1.00C 11/1/84; site vortex.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!decvax!bellcore!vortex!lauren
From: lauren@vortex.UUCP (Lauren Weinstein)
Newsgroups: net.mail
Subject: Re: What happened here?
Message-ID: <775@vortex.UUCP>
Date: Tue, 3-Sep-85 12:51:04 EDT
Article-I.D.: vortex.775
Posted: Tue Sep  3 12:51:04 1985
Date-Received: Thu, 5-Sep-85 06:19:59 EDT
References: <186@ukecc.UUCP>
Organization: Vortex Technology, Los Angeles
Lines: 36

The problem noted has been occurring with ihnp4 for quite sometime.
The issues are actually quite interesting.

Site ihnp4 apparently tries to rebuild the From: (and at least
sometimes also the To:) line(s) based on the information already
on those lines.  Unfortunately, this munging often has undesirable
results, since it only results in the correct munging if all
previous sites have ALSO munged the From: line as the message passed
from point to point, and only if ALL munging was done "correctly" at
all points.  

If munging is to be done at all, it should be based on From_ info,
NOT From: info.  The From_ info can generally be relied upon to
include all uucp sites along the path, while the From: path may not.

Note, however, that in many cases (and this situation will become more
and more common) the correct thing to do is NOT to munge the From:
line AT ALL.  Especially when the line is already in @-domain form, 
it should be left alone and NEVER munged.  In fact, my own opinion is 
that munging of ANY From: lines (whether or not an @-domain address is
present on them) is a very bad idea.  The From: lines should be left alone
except possibly when passing through the ad-hoc ARPANET gateways we
have now.  If munging is going to be done at such a gateway, it should
use the From_ info for parsing.

As domain addressing becomes more universally usable, even gateway
munging of From: lines will become undesirable.  In general then,
munging of From: lines is an ad-hoc thing that some sites attempt
to do now but that they often get wrong.  You cannot rely on 
every site munging the From: line at all, or doing it in a 
"reasonable" way when they do munge.  Best to leave the From:
line (and other 822 lines) alone and generally not munge.
From: lines can be used for replies in a domainized environment, or
the From_ info can be used for replies in the current ad-hoc situation.

--Lauren--