Port Fowarding with xFi

I recently attempted to get Port Forwading functioning on my gateway so that I can use my computer to host a gaming server for myself and friends.

After logging into 10.0.0.1 I saw that Port Forwarding is now done through xFi, cool seems simple enough. After finding the port forwarding area and opening the desired ports through TCP/UDP I tried to host the server. I myself was able to connect to it easily since I'm on the same network which let me know that the server itself is good to go, however none of my friends are able to join me.

I did some more research and have seen that a lot of people have issues with getting the xFi port forwarding working.
I also took the time to try several different port checker websites, all of which tell me that the ports are closed, despite it saying they are open through xFi.

Is there any fix to the fact that xFi port forwarding just doesn't seem to work?

I don't suppose there is any way to unlock the option to port forward directly from the router the way it used to, when people could actually get it to work.
I'd rather not have to buy my own modem just to be able to port forward either.