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From: time@tbomb.ice.com (Tim Endres)
Newsgroups: comp.mail.misc,comp.mail.uucp,comp.mail.sendmail
Subject: Re: Which headers may Sendmail re-write?
Message-ID: <1CE00001.p376wj@tbomb.ice.com>
Date: 5 Dec 90 11:57:58 GMT
Reply-To: time@tbomb.ice.com
Organization: ICE Engineering, Inc.
Lines: 54
X-Mailer: uAccess - Mac Release: 1.0.3


In article <208@frcs.UUCP>, paul@frcs.UUCP (Paul Nash) writes:
> The administrator of this particular machine feels that this is
> perfectly reasonable, and even desirable, so that mail gets routed
> the way that they think fit.  However, others of us think that this
> is not terribly sociable, and want our addresses left alone.
> 

Disclaimer: I am no email guru, just been into it a long time.

This is one of the longer standing debates in mail history.
The original philosophy in electronic mail design was that a mailer
look at the "envelope address" to work with a piece of mail and *never*
touch the "envelope contents".

This was fine with a single mailer and a single transport, but alas,
along came other mailers and transports. With the divergence of mail
mechanisms came the realization that the "envelope address" was sometimes
inadequate. To solve this, some mailers began to look at the internals
of the "envelope contents" to view the header information and better
perform their task. While this was viewed as "wrong", it solved the
problem at hand and created few of its own.

Then, along came sendmail! The dark force of the mail universe! :^)
For some reason, which I have never had fully explained, sendmail
found it not only necessary to view headers to determine the means
of transporting the letter, but to modify these headers in order to
assist in the routing and reply routing of the letter through other
sendmails.

Mailer purists will tell you that sendmail is evil and breaks the
most fundamental of rules. This is my attitude. However, sendmail
administrators often have good and valid reasons for doing what they
do. Clearly, sendmail performs its duties at many locations without
complaints.

I guess the bottom line is this:
   I have *never* met a sendmail installation that did not create
   problems by munging headers. This is a headache for the administrator
   as much as the mail user. Now granted, it may be only one problem
   out of thousands of letters, but sooner or later it happens.

As an aside, my mail server recently tossed sendmail away for smail3.
This was because 30% of the mail I sent bounced going out, and 40%
of the replies never made it back. I am sure that had the sendmail
been configured a little more the problem could have been fixed. BUT
smail3 fixed the problem right away. It left the headers alone!

tim.

-------------------------------------------------------------
Tim Endres                |  time@ice.com
ICE Engineering           |  uunet!ice.com!time
8840 Main Street          |
Whitmore Lake MI. 48189   |  (313) 449 8288


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