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Date:      Mon, 18 Nov 1996 08:34:12 -0700 (MST)
From:      Marc Slemko <marcs@znep.com>
To:        Robert Shady <rls@mail.id.net>
Cc:        roberto@keltia.freenix.fr, freebsd-hackers@freebsd.org
Subject:   Re: BoS: Exploit for sendmail smtpd bug (ver. 8.7-8.8.2).
Message-ID:  <Pine.BSF.3.95.961118082418.4525C-100000@alive.ampr.ab.ca>
In-Reply-To: <199611181015.FAA11340@server.id.net>

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[moved to -hackers from security.  It started with a discussion of
sendmail with uucp; I stated that sendmail still tries to use DNS no
matter how you configure it and you have to recompile it to make it stop.]

On Mon, 18 Nov 1996, Robert Shady wrote:

> > Incorrect.  It RUNS without DNS but still TRIES to use it.  If you really
> > don't have IP connectivity, then difference doesn't matter because it
> > still works when the lookup fails, however it still does try and the
> > difference does matter if you have partial IP connectivity.  I have a
> > system setup with nocanonify and all the other config file tweaks I know
> > of, and it still tries to use DNS as a tcpdump shows quite clearly.  This
> > system is running 8.7.5, so things may have been changed in more recent
> > versions but I can't say for sure; if this has changed in more recent
> > versions, please let me know.
> > 
> > I _think_ the define that needs to be set to 0 is NAMED_BIND, but don't
> > recall for sure.  This has been gone over before on the lists.
> 
> Out of curiosity, what interface exactly are you looking at if you aren't
> running tcp/ip?

I am running TCP/IP, however only sometimes; ie. a dial on demand
connection.  If it isn't recompiled, no matter how you configure it,
sendmail will try a DNS lookup for each bit of mail it receives, causing
the dial on demand link to come up.  I am looking at the ppp (tun0) 
interface.  If you don't have IP running, or you don't have a route to a
nameserver, or you don't have a nameserver, you won't notice the lookup
but it still tries and, in this case, fails immediately.





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