Fwd: IPv6 client and negative cache - some doubts

Sam Wilson Sam.Wilson at ed.ac.uk
Wed Feb 24 11:12:45 UTC 2010


In article <mailman.575.1266994115.21153.bind-users at lists.isc.org>,
 Michal Wesolowski <gmickyw at gmail.com> wrote:

> My server is caching only, I don't administer ns*.az.pl servers. I'm just
> trying to understand if binds copes well with such an external error. As you
> pointed out both servers fails in some (different) way but second one does
> this only when queried for something other than A record. For A everything
> is ok. THERE IS A record for virtual.jasnet.pl. Why bad response from
> external server for AAAA record affects subsequent queries for A? Which
> entry of cache is responsible for this:

These:

> virtual.jasnet.pl.      3597    A       85.202.208.254
>                         3597    CNAME   jasnet.pl.

You can't have both a CNAME and an A record for the same name.  I'm not 
sure which version of BIND you're using for your cache, but I'm slightly 
surprised it retains both records.

> Is it a case that unexpected response to AAAA query from ns10.az.pl marks
> virtual.jasnet.pl invalid even for A queries?

It looks like it.  

> Sorry for my persistence

Keep it up.  Now you need to talk to the az.pl people and persuade them 
their server is broken.

Sam



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