Recently we faced an issue on a Windows 2008 R2 domain controller where it stopped responding to DNS queries over a period of time as a immediate resolution we can reboot the server, it works OK for a few days and then it fails again.
We investigated NETSTAT output on the server, we found that DNS.exe is occupying a lot of ports on the server.
Open command prompt with elevated privileges on the server and execute following command to check the DNS.exe port consumption on the server
Netstat -ano >Output.txt
PS: Netstat output will show you PID not the process name, you will have to match the PID in task manager to find process name.
You can restrict the amount of ports used by defining a lower Socket Pool Size, as described in this article:
- Open an elevated Command Prompt (Run as Administrator…)
dnscmd /Config /SocketPoolSizewhere is a number between 0 and 10000
regedit.exeand expand the
- Navigate to
- If not already present, create a new
- Set a decimal value between 0 and 10000
- Restart the DNS Server service:
net stop dns && net start dns
On a long run, we found issue still re-occured, we were not able to true resolution to the issue, however as a workaround we scheduled the DNS server service on the Server to restart everyday. I will update this article if I we find the resolution to the problem.
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