RT-AC68, IP not updating in DDNS, using mobile hotspot & Openvpn

[sceptre]

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.

 

[Grisu]

Do you use asuscomm DDNS with Lets Encrypt? That's broken, fixed with newest 81351 firmware but have to wait for Merlin.

 

[Adamm]

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.

Not sure how AT&T does things, but assuming you are using a mobile connection there's a good chance you are using Carrier-grade NAT in which case you won't be able to connect to the router remotely as you share the same IP address with potentially hundreds of other customers.



Edit; Quick google search shows this is the case.