[Pdns-users] how do query the recursor cache to see what's in it?

Kenneth Marshall ktm at rice.edu
Thu Mar 10 14:00:11 UTC 2011

On Wed, Mar 09, 2011 at 03:13:03PM -0800, Alfred B. M. Cordero wrote:
> On Wed, 09 Mar 2011 14:30:23 -0800 Kenneth Marshall <ktm at rice.edu> 
> wrote:
> >You can use "rec_control dump-cache filename" but the
> >recursor will not answer queries while that cache is being
> >dumped.
> >
> >Have you checked your network gear to see if you are
> >discarding network packets. UDP is prone to that and
> >it could cause service problems. But I would not
> >attribute them to the recursor...
> Thank you Ken. rec_control worked great and I read about the 
> negative
> values.
> We have not seen this problem with other dns.

Another source of network problems could be caused by a
firewall device that tries to be too smart and either
delays the traffic or outright mutilates it. I do not
know your setup, but we dealt with an issue caused by
the security features of pdns-recursor, the randomized
source port.


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