FaceTime troubleshooting: use FaceTime behind a firewall
So you saw the latest iPhone 4 commercial and fell in love with FaceTime. You bring your iPhone 4 home, and you attempt to make a FaceTime connection with a friend… but nothing happens. What’s going on? It’s probably the wireless networks firewall settings.
I was recently speaking with an Apple employee and they told me that most of the problems people are having with FaceTime connectivity have nothing to do with the device itself, but instead it’s almost exclusively an issue with the network it’s being used on.
If you’re having problems connecting to FaceTime on a WiFi network, be sure the following ports are forwarded (or open) on the firewall: 53, 80, 443, 4080, 5223, and 16393-16472 (UDP).
Apple has dealt with enough of the port forwarding issues to release a support article on the topic, which is where the aforementioned port numbers are from. FaceTime isn’t alone here though, this is actually a really common problem with computer based video chat services like Skype and iChat too, and having the ports straightened out almost always solves the issue.