ns record caching question

[Larson, Matt]

> On Mon, Jul 17, 2000 at 04:19:45PM -0400, Wayne S. Gabree wrote:
> > 
> > If the root nameservers point to ns1 & ns2, but the ns 
> records on ns1 &
> > ns2 are ns3 & ns4, which ns records will get cached and 
> used for future
> > queries?
> > 
> > In other words, does a nameserver get the ns records from the
> > authoritative servers, keep them and throw away the ns 
> records it got
> > from the root name servers?
> 
> ISTM that ns3 and ns4 are kept.

And, just to clarify, only ns3 and ns4 are retained by the querying name
server: the NS RRset in the child zone overrides the delegation NS RRset.
The mechanism in BIND that implements this behavior is called credibility.
Also see RFC 2181, section 5.4.1; the trustworthiness ranking of data in
that section is similar to what BIND implements.

Matt
--
Matt Larson <mlarson at netsol.com>
Network Solutions Registry / www.nsiregistry.com