apple tv ports
which ports does apple tV use and how do I change these ports im my proxi?
Apple TV
http://support.apple.com/kb/ht2463
more hits here
about how you change it in your proxy very much depend on if it's the firewall on the computer or in the wifi router
buttom line is if you are not used to messing around with such things or comfable following guides you google
you may want to get somebody else to handle the network settings part