does bind caches no replies ?

bert hubert ahu at ds9a.nl
Sun Feb 16 14:23:00 UTC 2003


On Sat, Feb 15, 2003 at 11:11:20AM +0400, Ladislav Vobr wrote:

> discovered that  50% of all my requests (around 1000/sec) are to some
> specific domain. ( this case happen to me several times in last few
> days, with infopak.gov.pk or with nopop.net ) All nameservers for those
> domains were at that time unreachable and were not responding at all.
> What I have noticed is that for each request I get from customer, my
> nameservers sends 2-3 requests to each NS records it has for this domain
> to retry again and again.

This is a nasty problem plagueing many recursing nameservers. The PowerDNS
recursor implements query throttling to prevent misbehaving clients from
further harming remote nameservers: http://doc.powerdns.com/x1814.html

Your clients will still waste your CPU though, to a certain extent.

Regards,

bert

-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO
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