Intermittent NXDOMAIN for a name we are forwarding

[Matus UHLAR - fantomas]

On 19.02.16 17:08, blrmaani wrote:
>We have a DNS setup where we forward a name in one domain to 5 external
> nameservers.  We see NXDOMAIN error intermittently (once in couple of
> weeks).  How do I debug this issue?

tcpdump?

>I took a cache dump on our DNS and 2 out of 5 nameserver IPs appear in "Unassociated entries" when the problem happens.

anything more isble in the cache?

last time I have encountered this error, it was problematic Cisco DNS load
balancer, responding NXDOMAIN to a PTR (and possibly other) type queries,
while standard types returned proper answer.

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Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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