udp or tcp?
edited January 2011
How are facebook games that use photon like Paradise Paintball getting around firewall issues, are they using tcp instead of udp?
They use UDP.
Firewalls are fine with either UDP or TCP. Important is that the client (that sits behind the firewall) initiates the connection. As long as the firewall allows the outgoing packages to go through it should also allow the response packages - this is the case for both UDP and TCP.