Bind bind high recv-q

Cathy Almond cathya at
Fri Dec 4 22:13:24 UTC 2015

On 04/12/2015 12:34, Tony Finch wrote:
> Søren Andersen <SOAN at> wrote:
>> I'm experiencing some strange problems with my bind installation. - I
>> notice my bind recv-q is quite high sometimes.. therefore my DNS clients
>> can experience DNS lookup to take 1-4 secs. My bind is running on a 4
>> core vm I VMware with 8Gb ram. - At peak I receive app. 700-800 QPS. -
>> The load is 20-40% on each CPU core. - I've also configured 2 RPZ zones.
> Is your server an open resolver being used as part of a DDoS attack?
> Do you have compromised client machines running malware that hammers your
> server?
> Find out where the queries are coming from using netflow or tcpdump or
> query logging.
> Tony.

Also, if your server is not well-connected (if you have slow or
intermittent packet drops) between your server and the Internet, then
you might be affected by a defect in the prefetch implementation that
can impact performance for some server environments.

See and see if disabling prefetch
helps in your environment.

(The problem that this article talks about will be fixed in 9.10.4).

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