[Pdns-users] PowerDNS Recursor on multiple IPs within one machine

bert hubert bert.hubert at powerdns.com
Tue May 12 10:09:42 UTC 2015

On Sat, May 09, 2015 at 06:01:40AM -0700, Anton wrote:
> I am testing PowerDNS Recursor with adns resolver. It has adnshost command to
> check A records.

Hi Anton,

I don't entirely understand your question. If you do benchmarking tests, by
all means use a recent version of PowerDNS, check your network for
connection tracking (stateful) filters, check the powerdns startup log if
sufficient file descriptors are available, if you use IPv6 if you followed
the tuning instructions logged at startup.

If you do a test, enable performance graphing as described in

This allows you and us to see what bottlenecks you might be hitting.

Good luck!


> My machine is 
> Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz (8x3.40GHz)
> Ram is 16 Gb
> Async method of adns gives very very poor unstable results. 
> For example, if we check 100.000+ domain names of .pro domain zone handling
> 5000 domains by one request, the result will be very unstable and
> unpredictable. Up to 90% of existing domains could not be recognized. With
> 250 domains by one async request it works much slower than it could work in
> sync requests with same number of threads.
> If we use adnshost in "domain by domain" mode it gives rather complete
> result of exisiting A records.
> I have also used 120.000.000+ domain names list of .com .net .org .info and
> other zones to go through .co.uk zone with different number of threads to
> find optimal number of threads.
> With 1000 threads it will be 12-13 Mb of A records results.
> With 250 threads it will be up to 200 Mb of A records results. 
> So I want to understand what is it. 
> Currently in my tests it looks like root servers could cut some abnormal
> connections from one IP address.
> On other hand, 1000 threads works rather good on combined list of really
> existing domains like .com .org .net zones etc.
> 250 threads also works good but, of course, it is slower.
> --
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