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From: bhoule@se-sd.SanDiego.NCR.COM (Bill Houle)
Newsgroups: comp.sys.ncr
Subject: Re: mailx question
Message-ID: <4018@se-sd.SanDiego.NCR.COM>
Date: 12 Oct 90 07:40:19 GMT
References: <90284.094041TEMNGT23@ysub.ysu.edu>
Organization: NCR Corporation, Systems Engineering - San Diego
Lines: 63

In <90284.094041TEMNGT23@ysub.ysu.edu> TEMNGT23@ysub.ysu.edu (Lou Anschuetz) writes:

>Our NCR Tower 32/700 with UNIX V 1.03 is working quite nicely
>to send and receive mail via TCP/IP.  When it receives mail from
>another machine the mail daemon handles it correctly.  A mail
>header has the form:
>
>      From root
>      >From: otherguy@otherplace
>
>The only problem is that with mailx if you ask for the headers,
>all mail delivered via the mail daemon reports having come from
>root rather than the actual sender.

Actually, you probably get something more like this:

	From root _date_
	>From otherguy@otherplace _date_
	 <other headers omitted>
	From: otherguy@otherplace (real name)

Mailx typically uses the From_ line and not the From: line when
determining the sender address.  The second From_ is correct, but
unfortunately /bin/mail "comments it out" so mailx doesn't recognize
it.  Notice, however, that the From: line is perfect and unmangled.
To avoid the problem you are encountering, use another mail user
agent (such as Mush or Elm) that recognizes From: instead of From_.
If you don't like that answer, then read on....

The culprit in this case is /bin/mail, which is pretty much
brain-dead on all SysV boxes (the comments in sendmail.cf say as
much).  /bin/mail as delivered with the OS is not equipped to
understand external addresses and assumes that everything is a user
on the local system; this local user is simply determined by
$LOGNAME at the time of invocation.  To see what I mean, try this:

	% setenv LOGNAME 'bush@whitehouse.gov'
	% /bin/mail < some_file

Check your mail, 'cause you've got a letter from the President!  In
summary, /bin/mail is easily fooled.  It comments out any valid
From_ lines and adds its own according to the $LOGNAME of the
invoker.  Since sendmail is running as root, all incoming mail is
"From root".

The best solution is to get a better mail transport agent (a
replacement for /bin/mail), such as smail.  If that is too extreme
for your purposes, you could write a quick hack that:

 1) reads the first line of the sendmail generated mail
    (From user@node Fri Oct 12 00:08:15 PDT 1990)
 2) extracts the *real* address (user@node)
 3) sets $LOGNAME to this correct address
 4) pipes the remainder of the message to /bin/mail

From there, set the local delivery agent in sendmail.cf to this
kludge program (it is currently set to /bin/mail), and you are ready
to go.  It's a pretty trivial program to write, but I can send/post
mine if interested.

--
Bill Houle                       bhoule@se-sd.SanDiego.NCR.COM
NCR SE-San Diego                 (619) 693-5593