Fix WSL2 internet connection while on VPN

Tags: vpn wsl windows

Windows Subsystem for Linux (WSL2) provides native Linux environment for Windows. It's great alternative to cygwin which can't run native Linux apps. However WSL2 doesn't have out-of-box connectivity with internet once you connect with vpn.

Solution

Step 1

Open powershell and get the list of nameservers

Get-DnsClientServerAddress -AddressFamily IPv4 | Select-Object -ExpandProperty ServerAddresses

Step 2

Retrive search domains via powershell

Get-DnsClientGlobalSetting | Select-Object -ExpandProperty SuffixSearchList

Step 3

Open up wsl2, and run the following commands

# this will unlink the default wsl2 resolv.conf
sudo unlink /etc/resolv.conf 


# This config will prevent wsl2 from overwritting the resolve.conf file everytime you start wsl2
$ sudo bash -c 'echo "[network]" > /etc/wsl.conf'
$ sudo bash -c 'echo "generateResolvConf = false" >> /etc/wsl.conf'

$ sudo rm /etc/resolv.conf

# Add nameserver and search domain
$ sudo bash -c 'echo "nameserver 1.1.1.1" > /etc/resolv.conf'
$ sudo bash -c 'echo "nameserver 8.8.8.8" >> /etc/resolv.conf'
# Get following value from step 1
$ sudo bash -c 'echo "nameserver x.x.x.x" >> /etc/resolv.conf' 
# Get following value from step 2
$ sudo bash -c 'echo "search .com" >> /etc/resolv.conf'

# Make the new /etc/resolve.conf immutable
$ sudo chattr +i /etc/resolv.conf 

Remove any nameserver that starts with 172.* or 192.

Step 4

Restart wsl2 via powershell.

Restart-Service LxssManager

Finally you can connect to internet with vpn. To verify run the following command:

$ nslook www.google.com