# Client problem finding internet DNS name



## purge11 (Aug 22, 2007)

We have a windows 2008 r2 server and it is implement shares to 2 of our machines. The win 2008 r2 server does not do an DHCP role for now, the router is doing that for a while.

The problem is on the client, we point the DNS to the server so GPO's can work, but after a day the internet on the client goes down.

This is because I changed the DNS on the client from 192.168.1.1 (router) to 192.168.1.122 (server). I have read up on DNS issues and decided to add a forwarder on the servers DNS settings to our ISP IP address (which is static). 

However I do not really want to place DHCP role on the server as yet, but do not want to move DNS back to 192.168.1.1, because the clients take ages to log in and the GPO's will not work.

What can I do to make sure that the Internet does not go down after a day? The main problem is the clients cannot resolve the routers DNS, even if I set it as alternative on the clients IP settings.


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## credible58 (Apr 21, 2012)

Hi,

I'm not completely clear what you mean. I guess your setup is something like this:










I also believe that you have set the Preferred DNS Server on the user PC to 192.168.1.122 in the TCP/IPv4 properties for the LAN adapter. This being the case, the DHCP setup will make no difference. Even though your DHCP server may offer DNS settings, if on the user PC you have taken the option 'Use the following DNS addresses:' the DHCP values will be ignored.

On the Windows 2008 r2 Server you should set Forwarders - which I believe you have done.

Therefore, your configuration should work.

The reason that it all works for a day and then fails is probably because of DNS caching. There are DNS to IP addresses cached on your Windows Server, on the user PC and in your browser. These might work for a while but then expire.

To troubleshoot the problem try the following:


Open a command box on the Windows Server and enter 'nslookup www.advance7.com' (I assume that you've never been there before)
Confirm that the Server that gives you the answer is 192.168.1.122
Confirm that the name resolves to an address
If not, review the Forwarders configuration
If the above works OK, open a command box on the user PC and enter 'nslookup www.harpers.co.uk' (I assume that you've never been there before)
Confirm that the Server that gives you the answer is 192.168.1.122
Confirm that the name resolves to an address
On the user PC, review the TCP/IPv4 Properties, in particular the DNS settings
Best regards...Paul


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## srhoades (May 15, 2003)

You need to make sure the router DHCP scope is giving out the server as the primary DNS address. If you are on a domain (which sounds like you are since you are using GPO's) clients must always point to a domain controller for DNS.


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## purge11 (Aug 22, 2007)

Thanks for taking the time to reply to me. Your diagram is spot on and It really helped what you have wrote down for me. Luckily I read up about DNS problems and the change I did on the DNS settings off the win 2008 server worked.

So long as the ISP address is static, all should be fine now.


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## purge11 (Aug 22, 2007)

I also ran the command and here is what I got

C:\Users\Administrator>nslookup www.advance7.com
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
Name: www.advance7.com
Address: 82.165.203.202

Although I shouldnt be in as admin to do that command, but all seems be working ok. Btw, what does it mean by non-authoritative answer?

Thanks


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## purge11 (Aug 22, 2007)

Thanks for your reply shodes, your advice was most helpful.


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## credible58 (Apr 21, 2012)

Sounds good. The successful nslookup on your Win 2008 server just proves that your forwarder config is working. I should have said in the earlier post that an answer from 127.0.0.1 is also OK since this is the localhost address i.e. the address of IP-based services (like DNS) running on the same machine.

Best regards...Paul


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