How do I only allow a specific port (RDP) to connect over a WatchGuard VPN client?

Question

My office uses the WatchGuard VPN client to access the corporate network. I have a lot of services (e.g., Plex, VLC, Skype, etc) that I don't want to go over the VPN. The only thing I want going over the VPN connection is RDP.

It does not appear that I can this from the client, so I need to do this in Windows. I didn't see anything looking through the firewall settings, and routing tables don't appear to allow restrictions on a port.

Is there a way to restrict what ports are allowed over the VPN?

Thanks, Erick

Answer 1

If the "client" device is a Linux box it would be easier to do on the device.

If you want to do it on a Windows machine, it's still fairly easy, you need to open Windows Firewall and go to Advanced Settings, right click on Outbound Rules and click New. Create new outbound port-based rule(s) to block every port other than 3389 to whatever interface or subnet your corporate network is on. You'll probably need four rules, two for TCP (port 0-3388 and ports 3390-65536), two for UDP.

If there's a dedicated NIC to the corporate network you could just set the default action to block all and create an allow rule for RDP