The lowest and highest numbers for WPA2's are 1 and 999. When you chose a number it tells you if it's too high, or too low. The best way to figure out the port is to start choosing numbers in the hundreds, and once you've reached a point between two hundreds (like 300 & 400) go to the tens (like 350), and then to units.
 "Idle Hacking"){kind=icon}