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

---

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

In the wsl2 docs I noticed a comment on using Mirrored Networking mode being that it offers better compatibility with VPNs Maybe that's worth looking into for the complaints around the random subnets issue. Or not. Unsure. https://learn.microsoft.com/en-us/windows/wsl/networking#mirrored-mode-networking But either case had no issues with dns resolv.cof on wsl2 ubuntu lts 2024-04