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

Kenneth Marshall ktm at rice.edu
Thu Mar 10 18:25:14 UTC 2011

On Thu, Mar 10, 2011 at 08:49:02AM -0800, Alfred B. M. Cordero wrote:
> >
> >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.
> djbdns also uses randomized source ports (don't all dns now?) but 
> shown no
> similar patterns.  Our env. is a simple LAN running pdns recursor. 
> No other dns
> on the LAN.
> We are looking at bandwidth-limiting by the isp. If we have 256Kb 
> link we don't
> know how that is capped. But as you say,  they are maybe mutilated.
> Once at 256Kb any other traffic is dropped. There are probably many 
> different ways
> to do bandwidth-limiting.
> If there is anything we can do we will try it. Maybe we can do 
> something with QoS.
> But it is a new area so if you have any hints to share it may help.

Wow! That is not a lot of bandwidth. If you are pegging your
cap, responses may be taking a longer while to be returned and
pdns-recursor is timing out. Have you tried increasing the
value for network-timeout over the default 1500 ms?


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