root servers and ipv6

[JINMEI Tatuya / 神明達哉]

At Tue, 9 Oct 2007 16:30:14 -0400 (EDT),
hubcap at CLEMSON.EDU wrote:

> I'm to understand that the root nameservers should rarely be queried.
> 
> I would expect the root nameservers to be hit when bind restarts as
> the initial queries for this.com and that.net are fielded, but once
> bind has cached the servers for most of the top level domains (com and net
> and edu and ...) the root nameservers should mostly be left alone.

That's true, but named may still send out queries to the root servers
when it tries to fetch missing glue records (e.g. when the cache has
NS records for a domain but no address (v4/v6) information about the
server domain names).  So, it's not necessarily surprising to see a
query for a name under a well known TLD (like com) even after the
server should already cache information about the TLD.

In such a case named should usually ask for both A and AAAA records at
the root servers.  There may be cases where only AAAA records are
asked, but I suspect it's relatively rare enough.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei at isl.rdc.toshiba.co.jp