Apple FaceTime Tech Geekiness Ahead: TCP, UDP, and SIP Revealed

Put on your propeller hats folks, there’s a pair of extra tech-geekie links ahead. The first is from Apple itself. Support document HT4245 helps you get FaceTime video calls working if your WiFi network is behind corporate firewalls that are secured a bit tighter than the usual home networks. You’ll need to work with the network administrator to open up TCP ports 53, 80, 443, 4080, 5223 as well as a range of UDP ports 16393-16472.
iPhone 4: Using FaceTime behind a firewall
Next up is a piece of digital protocol detective work from one Arjun Roychowdhury who analyzed the bits involved in a FaceTime video call and shed some light on the signalling protocols involved (the Sessions Initiation Protocol – SIP – as it turns out).
Facetime on Iphone 4: Vanilla unencrypted STUN and SIP
Feel free to remove your propeller cap for the rest of the day after reading those two items.