No network access from WSL/Ubuntu

Microsoft Windows [Version 10.0.19043.1081] Ubuntu 20.04.2 LTS

I worked through the instructions for installing wsl for windows 10, from: https://docs.microsoft.com/en-us/windows/wsl/install-win10

However, I cannot connect to the internet from Ubuntu. I switched off the firewall as suggested here: https://docs.microsoft.com/en-us/windows/wsl/faq#why-do-i-not-have-internet-access-from-wsl-

But still could not connect.

There are a few things I have tried already but they did not resolve the problem (see below). As in the FAQ page: https://docs.microsoft.com/en-us/windows/wsl/faq#where-can-i-provide-feedback-

Thanks!

From Ubuntu terminal I tried to install: curl https://get.volta.sh | bash (6) Could not resolve host: get.volta.sh

so I tried: ping 8.8.8.8 ping: connect: Network is unreachable

I already posted a request for that but the problem is network access: [https://askubuntu.com/questions/1348348/trying-to-install-volta-sh-package-library]4

Some of the troubleshooting steps I have tried (which did not work)

1. Disabled the firewall.
2. Re-installed ubuntu.
3. BT (my internet provider), port forwarding: https://www.bt.com/help/broadband/learn-about-broadband/how-do-i-set-up-port-forwarding-on-my-bt-hub-
4. Checked Network Connection settings
   Ethernet Properties
   vEthernet Properties (WSL)
   Hyper-V Virtual Ethernet Adapter
   Internet Protocol Version 4 (TCP/IPv4) -checked
   Internet Protocol Version 6 (TCP/IPv6) -checked
   Hyper-V Extensible Virtual Switch -unchecked
5. Checked Device Manager (View Hidden) Network adapters > Hyper-V Virtual Ethernet Adapter Properties
   Device status - This device is working properly.
   
6. Turn Windows features on and off
   Uncheck Windows Subsystem for Linux
   Windows needs to reboot your PC to finish the requested changes
   Recheck Windows Subsystem for Linux
   Windows needs to reboot
7. Change the nameserver sudo nano /etc/resolv.conf
   '# This file was automatically generated by WSL. To stop automatic generation of this file, add the following entry to /etc/resolv.conf
   '# [network]
   '# generateResolvConf = false
   nameserver xxx.xx.xx
   Change the name server to 8.8.8.8 and save the file. You should now be able to connect to the internet.
   -even restarted ubuntu, same error after restarting and the nameserver seems to be reset to default
8. Flush DNS Open Powershell or Cmd as Administrator
   and run each of these commands:
   wsl --shutdown
   netsh winsock reset
   netsh int ip reset all
   netsh winhttp reset proxy
   ipconfig /flushdns
   Hit the Windows Key,
   type Network Reset,
   hit enter.
   You should see this window.
   Click "Reset now".
   Restart Windows

This issue started occurring for me after installing a corporate Cisco VPN package. I narrowed it down to incorrect weights on the virtual network adapter. The solution for me was to install https://github.com/sakai135/wsl-vpnkit, which resolved everything without additional configuration.