Fix DNS resolution in WSL2

fix-wsl2-dns-resolution

More recent resolution:

1. cd ~/../../etc (go to etc folder in WSL).
2. echo "[network]" | sudo tee wsl.conf (Create wsl.conf file and add the first line).
3. echo "generateResolvConf = false" | sudo tee -a wsl.conf (Append wsl.conf the next line).
4. wsl --terminate Debian (Terminate WSL in Windows cmd, in case is Ubuntu not Debian).
5. cd ~/../../etc (go to etc folder in WSL).
6. sudo rm -Rf resolv.conf (Delete the resolv.conf file).
7. In windows cmd, ps or terminal with the vpn connected do: Get-NetIPInterface or ipconfig /all for get the dns primary and
secondary.
8. With the dns primary and secondary getted replace the numbers in the next step in the X.X.X.X
9. echo "nameserver X.X.X.X" | sudo tee resolv.conf (Create resolv.conf and append the line.)
10. echo "nameserver X.X.X.X" | sudo tee -a resolv.conf (Append the line in resolv.conf)
11. wsl --terminate Debian (Terminate WSL in Windows cmd, in case is Ubuntu not Debian).
12. sudo chattr +i resolv.conf
13. And finally in windows cmd, ps or terminal:
Get-NetAdapter | Where-Object {$_.InterfaceDescription -Match "Cisco AnyConnect"} | Set-NetIPInterface -InterfaceMetric 6000

Credit: @MartinCaccia, @yukosgiti, @machuu and @AlbesK:
https://github.com/microsoft/WSL/issues/4277
https://github.com/microsoft/WSL/issues/4246

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Original resoltuion:

1. Create a file: /etc/wsl.conf.
2. Put the following lines in the file in order to ensure the your DNS changes do not get blown away

[network]
generateResolvConf = false

3. In a cmd window, run wsl --shutdown
4. Restart WSL2
5. Create a file: /etc/resolv.conf. If it exists, replace existing one with this new file.
6. Put the following line in the file

nameserver 8.8.8.8 # Or use your DNS server instead of 8.8.8.8 which is a Google DNS server

7. Repeat step 3 and 4. You will see git working fine now.

Credit: https://github.com/microsoft/WSL/issues/4285#issuecomment-522201021

Here is my solution for this problem. Basically I have accumulated everything mentioned above: https://gist.github.com/ThePlenkov/6ecf2a43e2b3898e8cd4986d277b5ecf

• script removes all nameservers in /etc/resolv.conf and replaces them with actual IPs from powershell

sudo sed -i '/nameserver/d' /etc/resolv.conf
powershell.exe -Command '(Get-DnsClientServerAddress -AddressFamily IPv4).ServerAddresses | ForEach-Object { "nameserver $_" }' | tr -d '\r' | sudo tee -a /etc/resolv.conf > /dev/null

• script is configured as a boot command which is available in Win 11. If it's applicable for you - it helps a lot

This works for me! Thank you so much!

Here is my solution for this problem. Basically I have accumulated everything mentioned above: https://gist.github.com/ThePlenkov/6ecf2a43e2b3898e8cd4986d277b5ecf

• script removes all nameservers in /etc/resolv.conf and replaces them with actual IPs from powershell

sudo sed -i '/nameserver/d' /etc/resolv.conf
powershell.exe -Command '(Get-DnsClientServerAddress -AddressFamily IPv4).ServerAddresses | ForEach-Object { "nameserver $_" }' | tr -d '\r' | sudo tee -a /etc/resolv.conf > /dev/null

• script is configured as a boot command which is available in Win 11. If it's applicable for you - it helps a lot

thanks it worked for me

Didn't work like a charm. Thank so much

So here is my configuration
Version WSL : 2.1.5.0
Version du noyau : 5.15.146.1-2
Version WSLg : 1.0.60
Windows 11 version : 23h2 22631.3296

I don't know how it happened, but from the day to the next it stopped working.
I did the original resolution, but putting my router's ip worked.

Original resoltuion:

1. Create a file: /etc/wsl.conf.
2. Put the following lines in the file in order to ensure the your DNS changes do not get blown away

[network]
generateResolvConf = false

3. In a cmd window, run wsl --shutdown
4. Restart WSL2
5. Create a file: /etc/resolv.conf. If it exists, replace existing one with this new file.
6. Put the following line in the file

nameserver 8.8.8.8 # Or use your DNS server instead of 8.8.8.8 which is a Google DNS server

7. Repeat step 3 and 4. You will see git working fine now.

I noticed that the IP that's in the /etc/resolv.conf is the one indicated here (ipconfig /all)

Which is apparently the WSL Hyper-V firewall....
would it mean that the issue lies in the "forwarding" or letting through of that Hyper V firewall and the host ? at least for dns, the traceroute seemed to work fine

Maybe this will help someone (source)

Set-NetFirewallHyperVVMSetting -Name '{40E0AC32-46A5-438A-A0B2-2B479E8F2E90}' -DefaultOutboundAction Allow

As @gtedavid mentioned it seems like Hyper-V is blocking some outbound connection by default, for whatever reason.
My setup is with Mullvad VPN. I am also using Windows Firewall Control tool by Malwarebytes.

To add my Mullvad VPN DNS server to WSL, do ipconfig.exe /all and grab the DNS address under your VPN name. Then sudo nano /etc/resolv.conf and add:
nameserver <IPHERE>
I did have to set Local network sharing ON, on Mullvad VPN settings. Try that if you still have issues and you're using a VPN.