WAN IP is wrong, port forwarding not working

[tRiFFiD]

After using an RT-AC87U for almost 4 years, I picked up an RT-AX56U on sale. I also changed internet providers on the same day as I set up the new router.
I've got a custom DDNS script that was working fine previously on the old router, and after copying it across to the new one it works there too.

However, the problem is that on the main web interface of the AX56U, the WAN IP is different to the actual IP that my ISP is giving me.

For example, on the main router page it shows as being 100.65.167.xxx, but if I go to whatismyip.com or any other similar site, it shows as 103.106.88.xx.
The DDNS script actually updates the hostnames to the 103.106.88.xx IP address correctly, but none of my port forwards are working.
I have SSH enabled on the router (LAN & WAN) and can't SSH to it from another internet connection on either of the two IP addresses.
I have ports 80 and 443 forwarded to a nginx reverse proxy server inside my LAN, but they are inaccessable on both of the external IP's as well.

Has anyone ever seen this? I have disabled CG-NAT in my provider's portal, so that is not active as far as I can see.
I'm a bit stumped and not sure how to get this working, or to get the correct WAN IP to show up in the Asus web interface.

edit: forgot to mention, I am running Asus Merlin 388.2_2.

 

[ColinTaylor]

100.65.167.xxx is a CG-NAT address. Try rebooting your modem. This is an ISP issue.

 

[drinkingbird]

After using an RT-AC87U for almost 4 years, I picked up an RT-AX56U on sale. I also changed internet providers on the same day as I set up the new router.
I've got a custom DDNS script that was working fine previously on the old router, and after copying it across to the new one it works there too.

However, the problem is that on the main web interface of the AX56U, the WAN IP is different to the actual IP that my ISP is giving me.

For example, on the main router page it shows as being 100.65.167.xxx, but if I go to whatismyip.com or any other similar site, it shows as 103.106.88.xx.
The DDNS script actually updates the hostnames to the 103.106.88.xx IP address correctly, but none of my port forwards are working.
I have SSH enabled on the router (LAN & WAN) and can't SSH to it from another internet connection on either of the two IP addresses.
I have ports 80 and 443 forwarded to a nginx reverse proxy server inside my LAN, but they are inaccessable on both of the external IP's as well.

Has anyone ever seen this? I have disabled CG-NAT in my provider's portal, so that is not active as far as I can see.
I'm a bit stumped and not sure how to get this working, or to get the correct WAN IP to show up in the Asus web interface.

edit: forgot to mention, I am running Asus Merlin 388.2_2.

Your new ISP is using NAT. Port forwarding is not possible unless you get them to give you a real IP or use IPv6.

Is the new ISP wireless or satellite? CGNAT is common with them.

 

[tRiFFiD]

I upgraded my speed and it looks like during that process, the ISP had turned back on CG-NAT.
There is an option in my account toolbox to turn it off, which I've just done and it's all working perfectly now.

Thank you to you both for the replies!