Possible to find all zones served by a ns?

[Kevin Darcy]

Rene Nyffenegger wrote:

> Hi
>
> Is it possible to find all zones or domains that are served
> by a specific nameserver?

Short answer: no.

I'm always curious why people ask this question. Are these DNS admins
trying to monitor and/or automate the maintenance of their slave
servers?

Or are they users who want to know what zones a server serves so they
can (hopefully) do a listing of each zone to build up some sort of
private name database? For what legimtate purpose? The data changes so
frequently, and, besides, just because a server serves a zone doesn't
mean it'll let arbitrary nodes do zone transfers of it.

Or, is the purpose to try and find a server which serves a whole bunch
of zones so that one can point one's stub resolver at it and supposedly
get better query performance that way? That's just plain dumb, since
there are a whole bunch of factors which affect query performance
besides just whether a server is authoritative for a zone, and, besides,
if everyone starts pointing their stub resolvers at the "good" servers,
they'll get overloaded and stop being so "good", and if the admin is
worth their salt, they'll start restricting recursive queries. All of
sudden your stub resolver breaks, and now you have to go off hunting for
another "good" server. What a pain...

Lastly, what exactly is meant by "serving" a zone? If a server
selectively forwards for a particular zone, does that qualify as
"serving" that zone? Or what if the zone is defined as "stub" on the
server? If the question is: I want to find out if server X is
authoritative for zone Y, then why not check the NS records and/or
bounce a few queries off of it to see?


- Kevin