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List:       procmail
Subject:    Re: Really a sendmail question
From:       Philip Guenther <guenther () gac ! edu>
Date:       1999-02-27 16:44:22
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Bill Moseley <moseley@hank.org> writes:
>At 05:48 PM 2/26/99 -0600, Philip Guenther wrote:
>>>	/usr/lib/sendmail -t -oi -oem -ba
>>
>>Ick.  I would suggest avoiding ARPANET mode, as the sendmail people
>>want to get rid of it.  Indeed, it was missing from some of the 8.6.x
>>versions.  Specify the envelope sender directly using the -f flag
>>instead.
>
>Of course I should try it, but can I use the -f switch running as 'nobody'?
>
>   -fname      Sets the name of the ``from'' person (i.e., the sender of the
>               mail).  -f can only be used by ``trusted'' users (normally
>               root, daemon, and network) or if the person you are trying to
>               become is the same as the person you are.
>
>I don't think I fit into any of those.

The semantics have a changed a few times: originally, sendmail would
ignore a -f flag unless you were listed in the sendmail.cf as a
"Trusted User".  Someone finally pointed out that there were other ways
to do the same thing (like use -ba), so in version 6.28 in May of 1993,
Eric Allman made -f usable by anyone.

Later, in version 8.7, the concept of "Trusted Users" was restored,
however this time it just controls whether or not a
X-Authentication-Warning: header is added if the invoker tries to use
the -f flag to change the envelope sender to someone besides its own
username.


>What about this switch?   I'm not sure what 'implies' means here, but it
>would seem to, eh, imply that it works like the -ba switch, but in a better
>way.  Not sure if that 'implies' also means it looks at From: and Sender:.
>
>   -bs         Use the SMTP protocol as described in RFC821 on standard in-
>               put and output.  This flag implies all the operations of the
>               -ba flag that are compatible with SMTP.

Ah, no.  The -bs flag tells sendmail to ignore addresses on the command
line and just SMTP on stdin/stdout.  To do this, the program invoking it
has to set up a couple pipes then send back and forth command/response
pairs.  If you don't the details of SMTP, don't bother with this.


>BTW -- how does one get the version out of sendmail?

Okay, here is a good use for -bs.  When it enters SMTP mode, sendmail
sends a banner (required by the SMTP spec) which _normally_ includes
its version number.  (You sysadmin may have told it to lie instead, but
that's still relatively rare, I think.)

If you invoke sendmail with the -bs flag, then type "quit", you get
something like the following:

	lunen% sendmail -bs
	220 lunen.gac.edu ESMTP Sendmail 8.9.3/8.9.3/GAC-SUBHUB-2.43; Sat, 27 Feb 1999 10:42:33 -0600 (CST)
	quit
	221 lunen.gac.edu closing connection
	lunen%

So, the sendmail binary on lunen.gac.edu is version 8.9.3, the config
file is version 8.9.3, and the config file author (me) added a local
version string of "GAC-SUBHUB-2.43".


Philip Guenther

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