Blackhole for incoming queries only

8 msg	Forwarding environment questions
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1 msg	how to check if bind is compliled with the dlz ...
4 msg	bind crash with max-cache-size
1 msg	BIND 9.5 stats
4 msg	dnssec-keygen + Bind 9.4.2 RC2

Blackhole for incoming queries only
\ Chris Thompson (20 Nov 2007)
. \ Erik Freitag (21 Nov 2007)

2 msg	Change nameserver's ips
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2 msg	why can't resolved
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3 msg	Enable logging for a single zone in BIND 8.2.3?
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6 msg	Bind 8.4.7-P1 on Solaris 8
2 msg	Re: Resend: BIND 9.4.2 Release Candidate 2 is n...

Subject:	Blackhole for incoming queries only
Group:	Bind-users
From:	Chris Thompson
Date:	20 Nov 2007

Over the last couple of years we've been locking down our recursive
nameservers with increasing severity. By now, allow-query and
allow-recursion block everything outside the university networks,
so such host always get a REFUSED response. That doesn't stop
there being quite a few of them that go on generating substantial
numbers of requests (shown up by query logging).

I had wondered whether it would make sense to move from refusing
to ignoring, by specifying

options { ...
blackhole { ...; !ournets; any; }; // hard to get negated ACLs right!
...
};

But this turns out to be a supremely bad idea, because "blackhole" not
only stops BIND accepting queries _from_ those addresses - it also stops
it sending queries _to_ them. And of course most nameservers in the
world are not in "ournets" ...

Any ideas on how to achieve the desired effect?

--
Chris Thompson
Email: cet1