dns server

If the internet connection is up but DNS lookups fail after a flush/reset, use this order to isolate whether the problem is the client, the network path, or the DNS server.

1. Verify reachability to the configured DNS server. Open Command Prompt and ping the DNS server IP address:

      ping <DNS server IP>
   

   If the DNS server does not respond, the issue is more likely network connectivity between the PC and the DNS server. Note that ping requires ICMP to be allowed through the firewall.
2. Test name resolution directly with nslookup. Run:

      nslookup <computer name>
      nslookup <fqdn>
      nslookup <failing website or host>
      nslookup bing.com
   

   If the FQDN resolves but the short name does not, check the DNS suffix configuration on the NIC advanced TCP/IP settings.
3. Check for a cached negative DNS response. If the nslookup tests succeed but the system still fails for the same name, display the DNS cache:

      ipconfig /displaydns
   

   If the failed name shows Name does not exist, clear the client cache again:

      ipconfig /flushdns
   

4. Reset the Windows network stack again in the supported order if not already done. Run Command Prompt as administrator, then run:

      netsh winsock reset
      netsh int ip reset
      ipconfig /release
      ipconfig /renew
      ipconfig /flushdns
   

5. If the problem is on a local DNS server, test that server directly. From a client, run:

      nslookup <client name> <server IP address>
   

   Results indicate:
   • If the client IP is returned, the DNS server is working.
   • Server failure or Query refused can mean the zone is paused or the server is overloaded.
   • Request to server timed out or No response from server can mean the DNS service is not running.
6. If a Windows DNS server is involved, check the server side. Review these logs on the DNS server:
   • Application
   • System
   • DNS Server
7. If the DNS server is reachable but queries still time out, check whether UDP/TCP port 53 is being blocked by firewall rules.

If this is a home Windows 10 PC using a router or ISP DNS, the most useful immediate checks are steps 1, 2, and 4. If ping <DNS server IP> fails, focus on network connectivity. If ping works but nslookup bing.com fails, the DNS server path or DNS server itself is the likely issue.

References:

• Troubleshooting DNS clients
• Fix Ethernet connection problems in Windows
• Troubleshooting DNS servers