finding out parent DNS of local DNS or local forwarder (provided FQDN is not defined)

[Stephane Bortzmeyer]

On Tue, Jun 05, 2007 at 02:50:38PM +0530,
 Vishwas <ivishwas at gmail.com> wrote 
 a message of 73 lines which said:

> A parent DNS is a DNS that serves its subordinate forwarding
> DNSes. As you know, in some networks local DNS is nothing but a
> forwarder and forwards all incoming queries to another DNS - which I
> called parent DNS

Yes, but it is not very common. Most DNS resolvers talk directly to
the world.

Anyway, you cannot, with the port 53 alone, find out the forwarders of
your nameserver. You have to rely on other methods, such as tcpdump on
the wire, asking the friendly sysadmin or setting up a zone on a name
server you control, querying it from your machine, and seeing the IP
source address of the query.

> I want to find out how many DNS servers are there over the Internet
> and how they are placed, and connected to each other.

I am not sure it is a realistic goal.

> Another concrete way is to rely only on IP addresses and traverse
> the DNS tree upwards with +trace option.

+trace mimicks the behavior of a resolver, so it does not go upward
but downwards.

> In near future I would like to obtain all possible details of DNSes
> over the Internet and make a graph representing connections among
> DNSes.

If I were a teacher, I would not assign this job to a student. I do
not think it is realistic.