Hi I followed the whole SmartFox tutorial and made a working multiplayer game (just 2 characters in a box that walk around with and can chat) and that worked on my comp in i opened it up twice and connected the two. But when i sent it to my friend it wouldn’t let him connect. (Also i have the same problem with my remote desktop app, it works in my house internally but not externally). Why is this happening? I checked the firewall and the ports were open so the only thing i can think of is to access our router, but i don’t know the pass or user for it (yes i tried the routers default user/pass). So if anyone knows an alternate solution please tell me 
Are you port forwarding the incoming packets to the appropriate IP on your network?
http://portforward.com/
I actually don’t really know much about this stuff so im not totally sure what you said, but we only have one computer.
if you don’t understand what he said, you should try and search on Google and read about it. You will get the general idea after having read a few pages. Also if you lost your login info of your router you should contact the vendor support.