Allow through VPN PPTP Connection, block everything else

I could need some help. I’m connecting by PPTP to my VPN Server. This Connection is a WAN Miniport. Sometimes (rarely) the connection gets lost and all my programs use the normal way out. Can I block it somehow. If it’s through the VPN Network it’s allowed, otherwise not. WAN Miniport has no MAC-Address, so i don’t have a clue how to config this.


Sorry, couldn’t wait. I already changed to OVPN and so i have an additional virtual network card with an MAC adress. Then it was easy. But thanks for trying to help.