Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!cis.ohio-state.edu!karl_kleinpaste
From: karl_kleinpaste@cis.ohio-state.edu
Newsgroups: comp.mail.misc
Subject: Re: Which headers may Sendmail re-write?
Message-ID: <KARL.90Dec19171132@giza.cis.ohio-state.edu>
Date: 19 Dec 90 22:11:32 GMT
References: <276D119F.66B0@tct.uucp>
Sender: news@tut.cis.ohio-state.edu
Organization: Ohio State Computer Science
Lines: 30

chip@tct.uucp writes:
   my hypothetical message will arrive at osu-cis with the envelope:
	   From tct!chip
   but the header will be valid RFC822:
	   From: chip@tct.com
   Will this header be rewritten into a bang path just because the mail
   came in from UUCP?  I expect that it won't, since it's already RFC822.

Any header of the form localpart@some.reasonable.domain (which
specifically does not include .uucp) will be left entirely unmolested.
My sendmail.cf will notice the proper form, and immediately depart the
ruleset without modifying the address.  (Or, perhaps more precisely,
it will rewrite it in exactly the form in which it was found.  Either
way, a semantically null operation.)

   2.  (This is the example that sparked my original suggestion.)  If
   mail from BAR.COM is being delivered to TCT.COM via UUCP from osu-cis,
   will the headers:
	   From: foo@bar.com
	   To: chip@tct.com
   be rewritten into bang paths just because my site's transport of
   choice is UUCP?

Again, since it's in The Right Form, I don't touch it.  If what I got
was rather more complex (e.g., host!user@some.domain), then some
rewrites may be necessary as the message departs via UUCP to avoid the
imaginary ambiguity of @-vs-! precedence, but I never mess with pure
user@dom.ain syntax.

--karl