http://canyouseeme.org/Check to see if port 28000 is open.
If it isn't, connect to 192.168.1.1. Log in with your router username and password. They're usually admin.
Go to "Applications & Gaming".
Under the first empty slot for a port, enter "28000" into your "External port" and "Internal port" columns. Tick the "enabled" checkbox. Type in the last two numbers of your desktop's private IPV4 address.
If you don't know how to find your desktop IPV4:
Open up command prompt, type in ipconfig. Scroll to "IPv4 address". Voila.
