on TTL expiry BIND sends 'ANY' query, gets back 'NOANSWER'

Phil Mayers p.mayers at imperial.ac.uk
Thu Apr 9 11:31:14 UTC 2015


On 08/04/15 22:00, Chuck Anderson wrote:

> No, you are right.  My filtered view of the packet capture was missing
> the fact that another unrelated client did an 'ANY' query.  I found it
> in the query log.  BIND 9.10 implements prefresh, but I'm on 9.8.2.
>

Oops just saw this, disregard my other email.

> Thanks for your help!  It looks like whenever an 'ANY' query comes
> into BIND due to the load balancer misbehavior it causes 'NOANSWER' to
> be cached for the MinTTL.

Hmm.

>
> I will now go back to the load balancer vendor and see if they can
> make it answer 'ANY' queries correctly.

Well... TBH ANY queries are a minefield. They're really for debugging 
only. They're not meant to be some "fetch all types" DNS query for 
production use, despite what qmail would have you believe.

I would look to stop the client doing ANY queries. As Barry says, LB 
vendors take ages to get stuff like this right (why they can't just use 
an embedded copy of bind for their DNS crap I don't know; use DLZ if 
they absolutely must).


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