Kat's method is 50% right..
For one thing, if you don't know your router's protocol user/pass then reset the router by unplugging it, and reseting it manually(Reset button, etc.). Once done if you visit your protocol page, your account will be reseted to the following;
You can port forward from there if you know how depending on your router.
And if you have a comcast gateway, in that case it would probably be;
My router is
No I do not make game hacks anymore, please stop asking.