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How do I confirm what public DNS my internal DNS servers are set to use?

How do I confirm what public DNS my internal DNS servers are set to use. I have been asked this information by my ISP as we are having problems access a certain website through their connection.
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gpersand
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gpersand
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1 Solution
 
Ernie BeekExpertCommented:
Check if you have forwarders configured in your DNS server. If not, it should be using the root servers: http://www.root-servers.org/
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-CPG-Commented:
ipconfig /all at the command prompt.  That will show you how the server is set.  If the server is set to use an internal DNS server based inside the network and managing DNS for the domain then that will obviously not resolve remote addresses on the internet.  So if a client requires resolution of a remote host it will forward this on to the default gateway, this is most likely your firewall or router at the edge of your network.  Once onto that device it will resolve the request according to what is set in that device.  You will probably have some DNS servers for your ISP configured in the router.
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Ernie BeekExpertCommented:
So if a client requires resolution of a remote host it will forward this on to the default gateway

Sorry to correct you but this is only on an IP level. If a machine doesn't recognize the network (not directly attached or not in it's routing table) it will send the packets out its default gateway.
With DNS, if the configured DNS server(s) can't resolve the query they return an error.
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-CPG-Commented:
that must be why DNS resolution never works on any of the hundreds of windows domains I have setup over the last 10 years.
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Ernie BeekExpertCommented:
Well if it works that would have an other cause ;)

When you configure DNS servers on a client, the client only queries those servers. If one of the servers is able to resolve the query it will return that to the client. If it is not able to resolve, it will query any configured forwarders and return the resolved IP to the client (if any). If no forwarders are configure it should, by default, query the root servers directly and then return the resolved IP (if any).
The client and server only query the configured servers/forwarders/root servers. If these can't provide an answer and the server would sent the query out its default gateway, where would it go? The DG should resolve it? It can only do that if it is set up as a DNS server as well and in the querying machine it is set as a DNS server.............
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-CPG-Commented:
I have never had to research it as it has always worked for me.  For all I know everything you say may be completely true.  When something works I usually don't feel any desire to understand why it works so long as it is fairly obvious.  I have heard about the DNS forwarders before, I'm sure it's the case that Windows automatically configures forders when you install the DNS server in the Windows domain.
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Ernie BeekExpertCommented:
Not really. Forwarders have to manully configured (because normally that would be a server at your ISPs which differs for everyone). But by default windows automatically does set up the root servers (so your quite right about that :)

I was just pointing to the difference between routing and how DNS works to avoid any misconception.
And yeah, I'm one of those people who always has a dire need to figure out why and how things work (even when they say: it's working so do touch it ;)
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