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Date:      Tue, 19 Nov 1996 19:58:09 -0700 (MST)
From:      Marc Slemko <marcs@znep.com>
To:        Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>
Cc:        FreeBSD hackers <freebsd-hackers@freebsd.org>
Subject:   Re: sendmail without DNS (was: Re: BoS: Exploit for sendmail smtpd bug (ver. 8.7-8.8.2).)
Message-ID:  <Pine.BSF.3.95.961118180356.6920D-100000@alive.ampr.ab.ca>
In-Reply-To: <199611190042.BAA03594@uriah.heep.sax.de>

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On Tue, 19 Nov 1996, J Wunsch wrote:

> As Marc Slemko wrote:
> 
> > I have tried nocanonify, nodns, a service.switch file and perhaps a few
> > other things that I can't remember right now, but sendmail still tries to
> > do DNS lookups.
> 
> You must do something wrong.  I'm using a local nameserver, but as you
> can see, it's only used for local lookups:

...and if you are setup to use a remote nameserver then it will try to use
that.  Therefore, you aren't disabling lookups.  A local nameserver can
work around the problem though.

[...]
> 
> uriah # kill -STOP `cat /var/run/named.pid `
> uriah # (echo "/bind/s/^/#"; echo "w"; echo "q") | ed /etc/host.conf
> 105
> #bind
> 106

Aha.  This is a way of working around it that I had temporarily forgot
about.  With hosts before bind in /etc/host.conf, and an entry for the
local hostname in /etc/hosts, the lookup will be avoided. 

I forgot about that because there is some reason (can't remember it right
now; could be something that was fixed long ago) why I couldn't do that to
host.conf on the particular machine because it interfered with something
else.  However, in the general case for someone getting mail via uucp with
a dial on demand type network connection that will solve the problem. 

Thanks.

> uriah # echo "hi you" | mail -s "test mail" marcs@znep.com
> uriah # mailq
>                 Mail Queue (1 request)
> --Q-ID-- --Size-- -----Q-Time----- ------------Sender/Recipient------------
> BAA03279* (no control file)
> 
> (Well, that's the queue file from my /etc/daily that's just running
> right now.  Your mail did already go out to the UUCP spool by that
> time, no additional delay for nameserver attempts etc.)

If you don't have your machine setup so that it thinks it can reach a
nameserver outside and there is a route to that nameserver, you won't
notice any extra delays.




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