Portforwarding? EVER HEARD ABOUT?
You have to open a specific port(depends on the one you use)
Sorry but this is the first thing to chek. If you have never heard about Router and ports, please read the basics first wink

And ofcourse your neighbour needs your external IP and not the one of your Computer inside your local Area Network.

Check this first and tell me wink

Greets
Rackscha

MY Website with news of my projects:
(for example my current
Muliplayer Bomberman,
GenesisPrecompiler for LiteC
and TileMaster, an easy to use Tile editor)
Sparetime-Development