I'm playing behind a proxy and would like to know which ports to open in order to be able to play Magicka Wizards War (and not Magicka).
It seems that Magicka: Wizards War uses random ports from my own testing.
I tested it several times, and the result showed that it listened on port 15303, 15582, 16167, 17393, 17521 respectively in the tests.
It also used port 54254, 64594, 56102, 55128, 58629 for UDP respectively in the tests.
Therefore I suspect that this game will listen on a range of random ports and use a range of random port for UDP, but I cannot be sure for the actual range. I will update this answer when I get more information.