how can I find all the DNS servers on my network

[Bill Larson]

I'm jumping in a little late, but there are some additional
possibilities.

You could run a port scanner against all possible IP addresses on your
network, specifically watching for access to port 53.  Any system that
is operating a service on port 53 should be running a name server.  You
would have to perform this periodically to insure that you caught every
server.  Ugly, but possible.

Another possibility is to log all queries made to your name servers.
It used to be that older name server did not query on a random port,
but had their query come from port 53 to your server listening on port
53.  This characteristic would identify a name server.  Since name
servers are now sending queries from a random port, this isn't a good
solution anymore.

Now, as was pointed out, anyone can easily run a name server without
informing anyone.  This is their responsibility, not yours.  This is
part of the responsibility  associated with a distributed network
service such as DNS.

In general, you are asking an impossible question, or being asked to
perform an impossible task.  There is no way that anyone can insure
that everyone is updating their systems.

Bill Larson

> >>>>> "Julie" == Julie Xu <j.xu at uws.edu.au> writes:
> 
>     Julie> Is anyway to let me find out how many DNS servers in our
>     Julie> network?
> 
> Not really. You could physically check every computer on your net but
> who's to say if someone starts or stops a name server on it before,
> during or after the check?