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After upgrading my Windows 10 Pro to 20H2 I started experience strange name resolving delays. This is very uncomfortable, because every web-page open takes at least 15 seconds. Every console command, which makes DNS requests, takes at least 10-15 seconds per DNS request (for any new host).

For example opening superuser.com takes at least 10 seconds. Request is stalled in DNS resolve phase:

enter image description here

Upstream DNS resolver (my home router) on 192.168.33.1 responds to Windows DNS resolver immediately:

enter image description here

Resolving from console shows the same behavior:

$ time getent hosts superuser.com
151.101.65.69   superuser.com
151.101.193.69  superuser.com
151.101.129.69  superuser.com
151.101.1.69    superuser.com

real    0m11.092s
user    0m0.015s
sys     0m0.000s

Same situation with the other hosts:

$ getent hosts github.com
140.82.121.4    github.com
$ time getent hosts github.com

real    0m10.013s
user    0m0.001s
sys     0m0.000s

Upstream DNS resolver (my router) returns response immediately:

$ time nslookup superuser.com
Server:         192.168.33.1
Address:        192.168.33.1#53

Non-authoritative answer:
Name:   superuser.com
Address: 151.101.193.69
Name:   superuser.com
Address: 151.101.129.69
Name:   superuser.com
Address: 151.101.1.69
Name:   superuser.com
Address: 151.101.65.69


real    0m0.105s
user    0m0.000s
sys     0m0.031s

Build details:

OS Name Microsoft Windows 10 Pro
Version 10.0.19042 Build 19042

Edition Windows 10 Pro
Version 20H2
Installed on    ‎20/‎12/‎2020
OS build    19042.685
Experience  Windows Feature Experience Pack 120.2212.551.0

My intuition is that Microsoft experimenting in new Windows version with DNS over HTTPS or other "modern things" and broke DNS resolver. Problems can also be related to the feature, where DNS resolver tries to speed-up resolving by sending requests to multiple sources. Since AAAA requests do not positively responded (because the host does not have a AAAA resource), resolver waits for another response (from another interface) to satisfy it, until it timeouts. But this my theory has also a flaw, because I have only one configured resolver in OS: this is by router's DNS.

I disabled IPv6 protocol on all interfaces, but it didn't help.

Some people already started reporting the same, but not yet as a general DNS resolver/client issue.

Any ideas how can I work around this problem? I'd like Windows DNS resolver to respond immediately.

EDIT

Surprisingly, second time of netsh int ip reset as suggested by John and reboot seem to solve the issue permanently for both Windows and WSL2 environments. I did in meanwhile also Windows Update check & install, but it only brought a .net 3.5 update, which shall not have any effect on DNS client.

(1) netsh int ip reset c:\resetlog.txt

Very happy and grateful to the community! Happy New Year! 🎄⭐

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  • “My intuition is that Microsoft experimenting in new Windows version with DNS over HTTPS or other "modern things" and broke DNS resolver.” - This is definitely not the case. Even if it was the case it would not explain the delay. There is virtually no delay caused by encryption
    – Ramhound
    Commented Dec 25, 2020 at 0:49

1 Answer 1

Reset to default
1

My intuition is that Microsoft experimenting in new Windows version with DNS over HTTPS or other "modern things" and broke DNS resolver.

I do not think this is correct. My two 20H2 machines work fine as does my 21H new Insider machine.

Run TCP/IP Reset, DNS Flush

Open cmd.exe with Run as Administrator

(1) netsh int ip reset c:\resetlog.txt

(2) ipconfig /flushdns

(3) restart the computer

Test after restarting. This fixes many DNS issues.

If the issue remains, try DISM and SFC.

Open cmd.exe with Run as Administrator.

DISM.exe /Online /Cleanup-image /StartComponentCleanup

DISM.exe /Online /Cleanup-Image /Restorehealth

SFC /SCANNOW

Again restart and test.

Finally, if the sequence of steps above (that normally work), you may need to do a Windows 10 Repair Install

https://www.microsoft.com/en-us/software-download/windows10

Windows 10 is running, so click on the Download button (not Upgrade Button) and select Run. If the Repair will not run as per above, use the Download button to create a USB Windows Installation key, then run Setup on the USB Key.

This will launch the Repair and proceed normally.

Start with the option to Keep Everything.

You can also Keep Data, or Keep Nothing. Keep Nothing is very close to a clean install.

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  • (Strange that our comments from yesterday have disappeared) So far, resolver works correctly. I only did netsh int ip reset c:\resetlog.txt yesterday.
    – Anton Golubev
    Commented Dec 25, 2020 at 9:08
  • Perhaps you can mark my post as helpful as you had said it was helping.
    – anon
    Commented Dec 25, 2020 at 12:01
  • Sure John, your answer is helpful. I’m just waiting to be sure it does not reappear, which would mean we correctly identified the cause and the fix helped. Do you know what happened with our chat from yesterday? It just disappeared?
    – Anton Golubev
    Commented Dec 25, 2020 at 19:44
  • Chats go away after time and some community like members delete them. Not me though.
    – anon
    Commented Dec 25, 2020 at 20:45

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