Only those on your network can affect you through your LAN IP address, which is what Link is referring to.

By default, this number is usually 192.168.x.x, where x is a varying number.

Go to start-run, type in winipcfg.

Locate your network adapter in the list of adapters. Look at the default gateway, and write down the number. Look at the IP address, and also write down that number. Now type in what you saw in the default gateway box into your browser window's URL box. You may need a password to enter your router's configuration, and this fact varies by company. I could give you specific instructions if you have a Linksys router, but otherwise, you will need to refer to your manual to figure out the password and where the port forwarding options are.

Once you have gotten into your router's configuration page, locate the page where you can configure port forwarding. Type in the IP address you got from the "IP address" box in winipcfg, and set the range to ports 10052 to 10054, with TCP and UDP protocols both enabled for forwarding. Save these settings and try serving.

I have heard that some routers fail to forward UDP, which is an extremely bad thing for a router. We might be able to help you further if you provide the name of the brand of your router. Good luck.