Many '...query: . IN NS' in query log file

[Pete Ehlke]

On Thu Oct 07, 2004 at 08:35:32 +0000, Nicolas Ecarnot wrote:
>David Botham <DBotham at OptimusSolutions.com> wrote in
>news:ck1i5t$lso$1 at sf1.isc.org: 
>
>>> client 81.206.200.71#1026: query: . IN NS
>> 
>> I am fairly certain this log entry indicates that the computer at IP 
>> address 81.206.200.71 is asking your name server for the NS RR's for
>> the root zone.
>
>It seems clear, but is this normal that those servers asks that every ten 
>second ?
>Aren't they supposed to keep a cache of this kind of information ?
>

It may not be a server at all. There are a lot of poorly done stub
resolvers out there in the world (written in to web browsers, for
example) that do this sort of thing. It might be 'normal' for the
application that is doing the querying, but the liklihood that it is
'correct' is fairly low ;)

-Pete