Does it match your IP address? If so, than the only other thing I can think of is, you've forwarded the wrong port, not all of the ports, or maybe your router's firmware doesn't work very well. I flashed my router with DD-WRT (I encourage you to too if you're comfortable with the process, it's simple but dangerous if the flash goes wrong, which if you don't touch anything, nothing should happen) and DD-WRT has a very extravagant interface, UPnP, Port Forwarding, DMZ, QoS, etc.