Fwd: IPv6 client and negative cache - some doubts

Sam Wilson Sam.Wilson at ed.ac.uk
Wed Feb 24 11:16:48 UTC 2010


In article <mailman.564.1266963563.21153.bind-users at lists.isc.org>,
 Mark Andrews <marka at isc.org> wrote:

> In message <f677fefa1002230600n4694161cu315e5dd4beaaab02 at mail.gmail.com>, 
> Micha
> l Wesolowski writes:
> > 
> > After some reading my present understanding is that correct response to 
> > AAAA
> > query when there is such record in the zone and there exists another record
> > of different type for the same name - is to reply with empty answer and no
> > error (this applies to authoritative NS). So what ns10.az.pl does is not
> > consistent with specification.

That's correct.

> > However I'm still not sure if bind shouldn't cope with this somehow. I
> > understand that if it applied to final query for "www.goliszew.pl" than it
> > would be correct for bind to cache it as negative for all types of records.
> > But if it concerns bad respond for NS? - I don't know.

I don't either.

> Well one of the nameservers does not exist and the other is a CNAME.
> Both of these are fatal errors for the particular nameserver and
> as there are only two nameservers for the zone lookups fail.

I hesitate to take issue with you Mark, but the problem is also that one 
of the nameservers has either an A record or a CNAME depending on how 
you look it up (A or AAAA query), and his caching server is keeping them 
both.

> Add A records to the sincom.pl and jasnet.pl zones for virtual.sincom.pl
> and virtual.jasnet.pl respectively.

As the OP has pointed out that's not under his control, and if the same 
misbehaving servers are responsible there's the chance that both will be 
screwed up.

Sam



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