large organization nameservers sending icmp packets to dns servers.

Mon Aug 6 21:53:38 UTC 2007

On 6-Aug-2007, at 16:31, Peter Dambier wrote:

> John L wrote:
>> Um, unless I seriously misunderstand the client DNS cache wants to  
>> know which server is closest.  So it sends DNS queries to all  
>> three NS at the same time.  Then it waits for the answers.   
>> Whichever one answers first is the closest.  What am I missing?
>
> The bind_garbadge_collection_delay.
>
> From time to time bind goes to sleep, depending on the size
> and number of zones the nameserver does host.

I think you're talking about the performance of BIND 9 as a cache.  
This is pretty tangential, but there was a good presentation on work  
being done to fix that performance problem by Michael Graff at the  
recent DNS ops workshop in Chicago:

   http://public.oarci.net/files/dnsops-2007/Graff-BIND9-cache.pdf

Joe