If so, all you need to do to get it to work from behind WinGate (i.e. incoming through WinGate to VPN server), is to redirect port 1720 TCP to the VPN server in
GateKeeper->Extended Networking->Port Security->Connections from the Internet
There's no toggle for GRE protocol header support. It will automatically be handled by the ENS driver. You just need to forward port 1701, TCP and UCP to L2TP VPN host. I haven't tried this before, so at least I think it's that easy.
i tried both suggestions and open up port on wingate and redirected them to my vpn server. however when i try to connect from my home computer to the vpn server i always receive error 800. can you please advise? is there a program i can use to check if my redirection works properly?