Fix resolv.conf in Windows Subsystem for Linux, when WSL doesn't correctly generate it.

wsl-fix-resolvconf.sh

#!/bin/bash

TMP=`mktemp`
trap ctrlC INT

removeTempFiles() {
	rm -f $TMP
}

ctrlC() {
	echo
	echo "Trapped Ctrl-C, removing temporary files"
	removeTempFiles
	stty sane
}

echo "Current resolv.conf"
echo "-------------------"
cat /etc/resolv.conf

echo
echo "Creating new resolv.conf"
echo "------------------------"

{ 
	head -1 /etc/resolv.conf | grep '^#.*generated'
	for i in `/mnt/c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe -Command "Get-DnsClientServerAddress -AddressFamily ipv4 | Select-Object -ExpandProperty ServerAddresses"`; do 
		echo nameserver $i
	done
	tail -n+2 /etc/resolv.conf | grep -v '^nameserver'
} | tr -d '\r' | tee $TMP

(set -x; sudo cp -i $TMP /etc/resolv.conf)

removeTempFiles

Thank you for sharing this ✔️

@scasplte2 I'm glad if it helped.

Thanks!!!

This script fixes my resolv.conf and makes my VPN to work, using Cisco AnyConnect on Windows instead OpenConnect in WSL.

@ThiagoBarradas you're welcome

Thanks man!!!

@jhanssenfavaro you're welcome

Really great!

..also, if you want add some own lines to it - please - remember do

wsl --shutdown

in Windows cmd or powershell

Please note that at least one WSL session must be open to save your own resolv.conf for future sessions.

Unfortunately this did not resolve my issue (no pun intended)

For me it did not resolve too.

Thanks for sharing your script!

I created a new version for it here: https://gist.github.com/MatMercer/f7e25b9c8ce7ca40dd3b220346136d23

@raulvictorrosa you can try it.

Perfect! I still needed to run the following (Source: anyconnect WSL 2 - Windows Substem for Linux) to get enable the interface on the VPN

Get-NetAdapter | Where-Object {$_.InterfaceDescription -Match "Cisco AnyConnect"} | Set-NetIPInterface -InterfaceMetric 4000
Get-NetIPInterface -InterfaceAlias "vEthernet (WSL)" | Set-NetIPInterface -InterfaceMetric 1

But that doesn't provide the DNS resolution. The resolv.conf update was the missing piece.