When connecting an L2TP tunnel with a Windows client, by default, all internet traffic will go through this tunnel. To spare bandwidth and therefore keep the internet traffic out of the L2TP tunnel follow the guide below.
On Windows PCs, we need to uncheck "Use default gateway on remote network" and add routing on CMD. Please follow the steps below.
You can implement the split tunnel configuration by following the steps below.
- Right Click on your network connection icon in your taskbar and click on "Open Network & Internet settings":
- In the next window, click on "Change adapter options":
- Right-click the VPN connection adapter and click "Properties"
- Switch to Networking-Tab, select "Internet Protocol Version 4 (TCP/IPv4)" and click "Properties"
- In "Internet Protocol Version 4 (TCP/IPv4) Properties", click "Advanced"
- In "Advanced TCP/IP Settings" "IP Settings"-tab, uncheck "Use default gateway on remote network".
- Create route(s) based on your needs for your VPN connection in PowerShell.
Example with 192.168.1.0/24 as remote subnet and "Zyxel VPN" as VPN connection name:
Add-VpnConnectionRoute -ConnectionName "Zyxel VPN" -DestinationPrefix "192.168.1.0/24" -PassThru
You have now successfully activated split tunnelling on the VPN connection and also add an additional route through the VPN.