Changing DNS settings breaks internet connectivity

Question

Hello!

I am running Windows 10 version 20H2, build 19042.685.

When I try to configure manual DNS under my adapter properties, DNS no longer resolves and my internet does not function properly. Moreover, when I use a VPN service, the internet does not function, presumably due to the same issue.

Some notes:

• This is not related to my network. This machine has been taken to several different networks, and the issue has persisted on all of them. Moreover, I have configured several other devices on the SAME network as the Windows 10 machine, all of which can use custom DNS or VPNs with ease.
• This issue does not persist if I set my DNS to configure automatically.
• The DNS server I am trying to use is not blocked on my network. Again, I have tried this on several networks so this should not be a concern, but I specifically tested it on other devices and made certain that any and all DNS servers I was attempting to use were in fact not blocked on the network.

Troubleshooting steps already attempted:

• Disabling antivirus (Bitdefender)
• Uninstalling antivirus
• Restarting several times
• Trying to set custom DNS on WiFi as well as Ethernet adapters (internet works on neither when custom DNS is configured)
• Resetting TCP/IP using netshell "netsh int ip reset"
• Flushing DNS cache using "ipconfig /flushdns"
• Disabling IPv6
• Booting into Safe Mode with Networking and attempting to make DNS changes there
• Running Network Troubleshooter (it could not identify the problem)

Any further information on reasons this might be happening as well as possible solutions would be greatly appreciated!!

See screenshot for a visual representation of how I am changing my DNS resolvers. On the second page "Internet Protocol Version 4 Properties", I choose "Use the following DNS server addresses" and enter in my DNS resolver.

Answer 1

Hi,

try to reset the network: Settings> Network and Internet> Status, click on the side on Network Reset, follow the instructions.

If the problem persists, type services.msc in the search box and hit enter. Search the list, DNS Client, right click and choose Update.

Try again.

Answer 2

Thanks for the response.

I updated windows to 20H2 build 19042.928, uninstalled Bitdefender completely, and ran sfc /scannow as well as a few other command-line tools. sfc said it found and corrected a few corrupt files but after running that process and rebooting the DNS settings are still unable to be changed without breaking internet connectivity.

Answer 3

Hi,

try to completely uninstall Bitdefender antivirus via its proprietary removal software. During testing, only keep Windows Defender Firewall enabled. I suggest you to update the system, install all available updates. It seems to me that you are not running the latest build of Windows 10.

If necessary, scan the system files for errors or corrupt files. 

https://support.microsoft.com/en-us/topic/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system-files-79aa86cb-ca52-166a-92a3-966e85d4094e

Answer 4

Franco,

Just tried it. As soon as I check that box and set a manual DNS (Say OpenDNS for instance at 208.67.220.220), it runs the network troubleshooter and says the DNS server isn't responding. This is odd! I reached out to my network administrator, and they confirmed that they do not block DNS queries that go to remote DNS servers. I even tried changing the DNS on other devices on the network and it works just fine. Very weird!

Answer 5

Hi SPS (Sean S)") ,

after setting the manual DNS, you have selected the checkbox, validate settings upon exit?