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Date:      Mon, 04 Dec 2000 16:39:51 +0100
From:      Christoph Sold <so@server.i-clue.de>
To:        Nils Holland <nils@nightcastleproductions.org>
Cc:        questions@FreeBSD.ORG
Subject:   Re: Sendmail/Dial-Up-Question
Message-ID:  <3A2BBAC7.4080009@i-clue.de>
References:  <Pine.BSF.4.21.0012031125570.197-100000@natalie.ncptiddische.net>

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Nils Holland wrote:

> Hallo!
> I have the following question:
> 
> I have one machine configugred with ppp -auto -nat, so that it establishes
> a connection to the Internet whenever one of my other machines wants to
> send packets to the Internet. The other machines are, of course, set up so
> that their default route points to the ppp-machine.
> 
> So far, so good. Now, on the other machines I have sendmail running
> (sendmail -bd), which also works fine BUT whenever I turn on one of these
> machines, sendmail wants to look something up using the nameserver, and so
> the boot-process hangs until the ppp-machine has established a connection 
> to the Internet.
> 
> This bothers me a little. I wonder if there's a way to prevent sendmail
> from doing that, because I don't see a need for a ppp-connection being
> established every time I start one of my computers, only for allowing
> sendmail to do this one nslookup operation (I don't even know WHAT
> sendmail looks up...)
> 
> So... does anybody have an idea what I can do so that sendmail starts
> normally but does *not* establish / need a connection to the
> Internet? While this behavior is not really a problem for me, I'm just
> curious if I can do something against it...


Check for the IP sendmail queries, add it to the machines /etc/hosts 
file, then pray the IP never changes.
Don't forget to configure the resolver to search the hosts file before 
querying DNS.

Alternatively, start a caching-only namerserver, have ppp block DNS 
queries, or hack sendmail.cf to not issue DNS queries. All of those 
possibilities carry other consequences, thus I implemented the above 
mentioned solution at home.

HTH
-Christoph Sold



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