So you figured out that when you try and start a server that all the incoming traffic gets stopped by your router.  Here is the quick and dirty on how to get things going.  Click to read more

Port forwarding, the basics:

Here is a quick how to on port forwarding with the most common of routers, the Linksys.  Port forwarding opens up a small hole in your router and points it to a computer within your network that is running a server.  Remember that your router will block any traffic not originating from your network (in that respect it acts like a firewall of sorts).

1. You are going to need to get into your router, open up explorer and in the address bar type in 192.168.1.1
2. Enter in the admin password, just type the password.  The default pass is admin in case you haven't changed it.
3. Go to the Application and Gaming tab at the top and click it.
4. You are going to need to enter three things:  Service name, Port and your inside IP number.
5. Save your settings and exit.
6. When your friends are connecting they will need your outside (router's) IP number.
7. If you don't know the Router's IP you can check it at ipchicken.com

If you don't know what port to forward check your games documentation.  Just look up port forwarding and your games name.  I'll try and get you a list of the most common ports in the next article.