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From: mark@cbosgd.ATT.COM (Mark Horton)
Newsgroups: net.mail,net.mail.headers
Subject: Re: Do you rewrite "From:" lines?
Message-ID: <2628@cbosgd.ATT.COM>
Date: Sun, 28-Sep-86 11:09:54 EDT
Article-I.D.: cbosgd.2628
Posted: Sun Sep 28 11:09:54 1986
Date-Received: Tue, 30-Sep-86 07:28:02 EDT
References: <358@tc-jeff.fluke.UUCP>
Organization: AT&T Bell Laboratories, Columbus, Oh
Lines: 36
Xref: watmath net.mail:1991 net.mail.headers:800

In article <358@tc-jeff.fluke.UUCP> jeff@fluke.UUCP (Jeff Stearns) writes:
>Now that I've installed smail, a nasty question comes up.  Should our sendmail
>modify "From:" lines?

If you have a legal 822 domain From: line, and you modify it by sticking
your host name on the front, you violate RFC976 and 822, and your mailer
is badly broken.  Unfortunately, this applies to most 4.2BSD hosts, and
I think the bug is still in 4.3.  I think the problem is related to the
fact that the From_ and From: lines are tied together by sendmail, and
it's very hard to prepend to one without breaking the other.  One solution
is to install smail, which won't involve sendmail in ordinary pass-through
mail.

If you have a From: line written with bangs, then there are no standards
that apply, and you can just about do what you please with it.

But note that it's pointless to stick your host name on the front of a
bang path in a From: line to help out a reply command.  This doesn't
work unless EVERY HOP along the way sticks its name in, and since
System III and V don't modify the From: line, the message need go only
through one System V hop to render the From: line meaningless.  Berkeley
long ago gave up on expecting this to work - domains are a much better
solution to the reply problem.

>But all of our neighbors tack their sitename onto the "From:" line as well!
>There's gonna be lots of unreplyable(?) mail if we start playing by The Right
>Rules while everybody else is Doing What The Majority Does.  (Recall that
>4.2BSD /usr/ucb/mail sends replies to the "From:" address, not the "From"
>address.)
>
>What's a mother to do?

That mail is generally unreplyable anyway, so you really aren't breaking
anything by stopping an unsavory practice.

	Mark