M7000 Router with VPN GRE Error?
Trying to connect to my work VPN, the VPN works fine on my home WIFI but trying to connect using my 4g dongle it fails.
In the TP-Link router settings I changed:
NAT Forwarding > Virtual Servers and added the port forwarding details (1723 and IP: 192.168.0.21 with TCP)
-This should permit TCP network traffic on port 1723, right?
And then I turned off UPnP
But when I try to connect my windows laptop it says "Unable to connect - The VPN connection between the computer and the VPN could not be established. The most common cause for this failure is that at least internet device (for example, a firewall or a router) between your computer and the VPN server is not configured to allow Generic Routing Encapsulation (GRE) protocol packets."
Reading online it seems I may need to configure the network firewall to permit GRE protocol 47? How can I do this? Any advice please?