[Unbound-users] unbound occasionally does not answer

Felix Schueren felix.schueren at hosteurope.de
Thu Aug 13 17:28:34 UTC 2009


and sorry for starting a new thread when the last one is from June - I
subscribed only recently and the mail archive does not show mail ids.
Anyway, I'm referring to the thread from Attila Nagy: "No answers from
unbound occasionally" - we're seeing much the same symptoms (using
1.3.2), i.e. unbound sometimes not answering queries, and debugging is a
pain - we're running a load-balanced setup with currently 3 unbound
nodes, around 22k q/s, each unbound node doing ~6-8k qps. It usually
works fast & fine, but some queries appear to get eaten - we're getting
occasional dns resolution errors when using unbound as cache that we
never got with our dnscache (djb) setup. I've debugged as far as seeing
that the queries reach unbound (they get logged), but I don't know
whether unbound answered and the packets got lost, or if unbound simply
did not answer at all.

Any ideas on debugging this? "Occasionally" means a couple 100 queries
per day (out of roughly 1.1G total queries). My "exceeded" (jostle)
counter is 0, average number of waiting requests is <10 per hosts.

Kind regards,


Felix Schüren
Head of Network

Host Europe GmbH - http://www.hosteurope.de
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