Using an Asus Rt-AC68p router with latest Asuswrt-Merlin installed. I have a mobile hotspot (At&t) connected to its USB port and USB activated in the router. My computer is connected to the router and an internet connection is successful with this arraignment and my computer has a reported public IP address. I have previously set up DDNS in the router and configured OpenVpn as well when the router was connected to the local ISP (wired connection) and the OpenVpn connection worked at that time. When I tried to transition to using the mobile hotspot as the internet source the DDNS apparently is not able to continue to update to keep OpenVpn working. So I am unable to connect remotely. I have tried port forwarding the 1194 port and I have activated DMZ for the router, but it still doesn't work. There is msg on the router about the router having a private IP address and it suggests doing the port forwarding but it doesn't work. I found several mentions of resolving a double NAT situation and I found a couple of references to scripts that might be related to this problem, but although I could possibly get the scripts loaded on the router I'm no good at writing them. It seems to me there is way (script?) for the router to obtain the IP address and to continue to check it and make sure DDNS and the Openvpn are kept updated with the correct IP. I suspect someone has already solved this problem but I could not find it anywhere in my searches. If you can help me understand how to accomplish this or point me to the solution, it will greatly appreciated.