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Master DNS Servers - Please Explain

Is there such a thing?

         

Me_Again

4:49 am on Sep 11, 2002 (gmt 0)

10+ Year Member



Hi all,

I am most interested to know if there is a set of Master DNS servers around the world.

IE: Is there one say in Australia or close by in Asia somewhere that will be the last one t o be askedif a DNS server cannot resolve a host name etc.

I recall during a W2K course that there were a certain number of DNS servers around the world that were the last resort (so to speak) for name / IP resolution.

I look forward to anyone clearing this up for me.

Cheers from Oz

amoore

6:04 am on Sep 11, 2002 (gmt 0)

10+ Year Member



Sort of. There is a set of "root" servers that are responsible for knowing which nameservers are responsobie for which top-level domains. You can ask them things like "who is autoritative for .com, or .net?" These servers have names like a.root-servers.net and b.root-servers.net

They will tell you that the GTLD servers are responsible. You can ask those GTLD servers who is responsible for the domains you can I can buy. They are authoritative for domaains like .com and .net. You can ask them questions like "who is authoritative for example.com?". They will tell you which nameservers to ask about example.com or webmasterworld.com. These gtld servers have names like a.gtld-servers.net and b.gtld-servers.net. (for a while and still now to some extent these machines are the same as the above)

Those TLD servers will refer you to nameservers like ns1.example.com or ns2.westhost.net. You can ask those nameservers things like "what's the IP address of www.example.com?" or "what's an MX record for webmasterworld.com?" These are the nameservers that you or your ISP deal with to add zone records for your domains.

You asked a bit about some of these nameservers being last resorts when no one else is responding. That's not really the case. The requests don't propigate up the tree. If the authoritative nameserver doesn't know the answer, it won't refer you higher up. If a nameserver is not authoritative it may send you elsewhere, though.

This is a highly condnesed simplification of the system. There are a lot better places on the net to search for detailed DNS information. You might try hanging out in comp.protocols.dns.bind or something.

Me_Again

6:27 am on Sep 11, 2002 (gmt 0)

10+ Year Member



Thanks for that. The discussion came about as i was asked if there were any of these "root" servers in the world trade centre.
I was sure thast there were a couple in the states somewhere, as well as 1 in Japan, however I may be wrong on that one.

amoore

6:36 am on Sep 11, 2002 (gmt 0)

10+ Year Member



Looks like there's a map of the locations of the root servers at:
[caida.org...]

and some more useful information about how they (and a lot of other stuff) works at:
[tldp.org...]

Feel free to also try something like:
[google.com...]

Me_Again

6:51 am on Sep 11, 2002 (gmt 0)

10+ Year Member



Thanks very much amoore. I appreciate it.