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I have a Server 2012 domain controller which is unable to contact its own domain.

Troubleshooting has led to the discovery that whilst client computers can resolve addresses using the domain controller, the domain controller itself cannot. Furthermore, the domain controller is unable to resolve anything using any DNS server.

nslookup
Default Server:  UnKnown
Address:  192.168.1.102

> google.co.nz
Server:  UnKnown
Address:  192.168.1.102

*** UnKnown can't find google.co.nz: No response from server
> server 8.8.8.8
Default Server:  [8.8.8.8]
Address:  8.8.8.8

> google.co.nz
Server:  [8.8.8.8]
Address:  8.8.8.8

*** [8.8.8.8] can't find google.co.nz: No response from server
> server 127.0.0.1
Default Server:  [127.0.0.1]
Address:  127.0.0.1

> google.co.nz
Server:  [127.0.0.1]
Address:  127.0.0.1

*** [127.0.0.1] can't find google.co.nz: No response from server

I'm completely at a loss to explain why client computers can resolve via this server but it can't itself. Any ideas?

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This isn't quite a full answer, just a question/suggestion.

Is the DC having any other connectivity issues? Have you checked to see if outbound port 53 tcp/udp is blocked somehow?

You can use nmap to test this: https://nmap.org/book/inst-windows.html

  • Well, inbound DNS requests seem to work fine (the client gets sent the response which means the dns server is recursing fine), and I can ping IP addresses. It definitely seems to be something to do with the local stack. Interestingly I can ping netbios names but not full addresses – alt Aug 22 '16 at 9:48
  • @alt Please check if you can access port 53 outbound. It would explain everything. – Ryan Babchishin Aug 22 '16 at 14:30
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Run dcdiag command to get the domain controller status. Syntax open cmd with administrator privileges type dcdiag > c:\dcdiag.txt enter. You will find text file named dcdiag double click on it and read the entire file, you will find some errors related to DNS. https://m.youtube.com/channel/UC1Lrxap5OjbCUoZMl8VM00Q

  • It must be issue with DNS. DCdiag tool will help you fix the issue. youtube.com/channel/… – Inquisitive Minds Aug 19 '16 at 10:35
  • unfortunately dcdiag doesn't help, as the domain controller cannot resolve any dns, and therefore cannot find the domain – alt Aug 22 '16 at 9:41
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Check the services manager (services.msc) and ensure the dns client service is running, and that in your networking settings you have the DNS server (for the NIC on the DNS box itself that connects to the interblag) set to 127.0.0.1.

Since nobody else is having DNS issues that are connected to the server daemon, it's not likely to be a server side problem (but rather client services on your DNS box itself - which do not affect server functionality at all).

  • yep, the dns client service is running. Changing the DNS server to 127.0.0.1 doesn't have any effect either. – alt Aug 22 '16 at 9:42
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Well, not really the answer I wanted, but rebooting the server has made the problem go away. If it comes back I'll look into it more.

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Rebooting sometimes fixes many issues. However, every domain should have RODC running. In addition, secondary DNS Server should also be running on any member server will be helpful to clients in case Primary DNS Server fails.

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