Opening ports for server

[reboundwhat7]

i forgot how to open them and I have a lynksys router ive openned them before and it worked but forgot
how do i do it? i want 27015 open heres a pic i kno i didnt do it right
http://img107.imageshack.us/img107/5290/dsadasrs9.gif

[Drocona]

Almost correct, you have to enter your server IP address in the box it says .1.

go to start>run>cmd *hit return* then type ipconfig in the console box, you'll get a list of numbers, take the IP address of that and put the number behind the last dot on the place of the 1