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Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!husc6!seismo!gatech!rayssd!gmp
From: gmp@rayssd.UUCP
Newsgroups: comp.mail.headers
Subject: Re: overuse of Received: headers
Message-ID: <834@rayssd.RAY.COM>
Date: Wed, 8-Apr-87 21:01:47 EST
Article-I.D.: rayssd.834
Posted: Wed Apr  8 21:01:47 1987
Date-Received: Sat, 11-Apr-87 09:50:36 EST
References: <1676@lsuc.UUCP> <323@dcl-csvax.comp.lancs.ac.uk>
Sender: gmp@rayssd.RAY.COM (Gregory M. Paris @ Raytheon Company, Portsmouth RI)
Reply-To: gmp@rayssd.RAY.COM (Gregory M. Paris)
Organization: Raytheon Company, Portsmouth RI
Lines: 25
Summary: Determining Received: from; how?

In article <323@dcl-csvax.comp.lancs.ac.uk> stephen@comp.lancs.ac.uk (Stephen J. Muir) writes:
> The machine the header says it is received *from* should be calculated by the
> receiving host by, say, a reverse lookup on the DoD Internet table given the
> n.n.n.n address the mail connection originated from or, say, the UUCP system
> name that was in use at the time of the transfer.  This is the basis of
> authenticity checking.

The ARPA/ethernet host name lookup is easy, and sendmail already does this.
But what about the uucp case?  How can sendmail find out the "system name
that was in use at the time of the transfer?"  If you know how to code this
in to sendmail, please let me know, cuz I haven't figured it out.  The sendmail
that we're running now (4.2BSD's version) doesn't do this at all.  I tried
figuring it out by looking at the argument passed to sendmail with the -f
flag, using the "last hop" part of the address, but now with domain-style
addresses being passed around via uucp, I've noticed that often this last
hop is some domain that we don't talk to at all.  Yipes!  Not much authenticity
there!  I ended up taking it out, since I'd rather say nothing than lie
(usually, anyway).

Suggestions?

-- 
Greg Paris ............................. gmp@rayssd.RAY.COM (a UUCP domain)
{cci632,cbosgd,gatech,ihnp4,linus,mirror,necntc,uiucdcs,umcp-cs}!rayssd!gmp
................................... What is your present form of execution?