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Path: utzoo!attcan!uunet!husc6!bloom-beacon!apple!claris!ames!killer!wisner
From: wisner@killer.DALLAS.TX.US (Bill Wisner)
Newsgroups: comp.mail.uucp,comp.mail.headers
Subject: Re: Real data to support my claim that '-d sun' is the way to go.
Message-ID: <5124@killer.DALLAS.TX.US>
Date: 7 Aug 88 19:43:28 GMT
References: <3703@palo-alto.DEC.COM> <10139@g.ms.uky.edu>
Reply-To: wisner@killer.DALLAS.TX.US (Bill Wisner)
Organization: HASA
Lines: 13

According to RFC822, the Return-Path header is added by the final
mailer that delivers the message to its recipient. It's supposed to
contain definitive information about the route back to the
originator. It's not supposed to appear in a message until the
very end of that message's travels. It's not supposed to be added
to as a message wends its way through the network.

The only MTS I know of that handles this correctly is Smail 3.1,
which puts a copy of the From_ line into a Return-Path line if a
message is being delivered by the "local" transport.

There is a compile-time option to MH that makes it transform From_
lines into Return-Path lines.