I have had Telecom ADSL, a static WAN IP and a domain name a very long time. I opened a pinhole/forwarding from port 80 to an internal machine with running www server on internal static IP LAN (192.168.1.22). Its been running very well for years no problems.
The Modems were upgraded to the 2Wire ADSL brand a few years ago and we gained an extra function. I could use my WAN static IP/domain name inside my LAN and it would loop back and I could see my web server ok.
A better example. I am inside my network (LAN) on a laptop DHCP 192.168.1.86. I use a browser and type in my WAN www (domain name) or WAN/Internet Static IP. I can see my webserver ok (and its on the same internal LAN). It makes life easy because I dont have to have a URL shortcut when inside my network and another outside. So I can loop out of my modem and back in between 2 machines in my internal LAN (192.168.1.86 to 192.168.1.22).
Now the upgrade to VDSL with a Huwei HG659 modem and I lost this function.
I think its in the modem setup and I need to loop my Hawei modem back to the Static IP like 192.168.1.254 --> Static WAN IP. Route.
But someone might be able to give me a hint.
Thanks for any input.