Re: djbdns: Current recommended patches?

On Tue, May 19, 2009 at 10:16:07PM -0500, David Nicol wrote:

> > dnscache has never used intentional query repetition, so there's no
> > need for the patch to make a distinction.
> 
> how often does a  second query arrive for the same cacheable name
> before a cached answer is available from the first query, in real
> world conditions, outside of an attack?

I don't have numbers, but this can easily happen when the querier hits a
timeout and asks again before the resolution is finished (which it must
do, since it has no idea if its original query even made it to the
cache). So it depends on time to resolve and client timeout.

-Peff