Any experiences in using loadbalancer for DNS ?

[David Nolan]

--On Wednesday, June 27, 2007 10:06:46 +0200 Udo Zumdick <uz at nic.dtag.de> 
wrote:

> Hello,
>
> we have a few nameserver running BIND 9.2.6 as a caching only NS behind 2
> Alteon 2208  loadbalancer in a active standby configuration.
> Now, when querying a domain that is not in the resolver cache, the
> respond for such a query takes more than 4 seconds, which is much too
> long. It seems that this is limited to UDP queries because the same query
> (dig [...] NS) with a +trace option takes mostly not more than a hundred
> milliseconds or so.
> Could it be possible that the loadbalancer is the reason for this delay ?
> Although I can't take it out of this setting.
>
> Has anyone an idea for a reason or has similar experiences ?


Are your outbound DNS queries from these servers being sent from the load 
balanced IP, and possibly being sent to the wrong server when the response 
packet is received?

Have you tried sniffing packets both inside and outside the load balancer 
to see what is happening?

-David