To see why (or what I think the reason is) look at the picture:
Ive got a Linksys Etherfast Cable/DSL router (wired) (model - BEFSR41)
I’ve tried port forwarding and went to that tutorial website and i just couldnt get it to work.
P.S. I’ve tried connecting directly to the Internet, but couldnt check if that was going to work as it (Windows 7) didn’t connect to the Internet