I formerly had a xampp server running that I could access from the web. All I did was change the DMZ IP on the router the the local IP of the server computer, and it all miraculously worked perfectly.
I then got a new modem. And it does most definitely not work the same way. If I go to my world IP, it does not load and eventually times out.
The setup is something like
World -> Modem -> Router -> Computers, one running a server.
So it's nothing special.
I believe it has something to do with napt on the modem, since DMZ is set up on the router.
What would be a good try? I have tried several things, but it doesn't seem to be changing all that much. At least not the way I want it to