FaceTime is a unique video calling feature that as of the iOS 5 still runs on a Wi-Fi connection, and will continue to be mostly used on Wi-Fi because of its incredible use of data. Because of this it can be presented with a problem when you are using a network that is protected by a firewall, which is used primarily to make the system much more secure from viruses, trojans, and outside accessibility. To use it correctly, you will have to alter the network that your mobile device is using so that you can continue to make video calls. Here is a look at how to prepare your firewall for using FaceTime on your iDevice.
For FaceTime to work adequately you have to open up certain ports so that you can actually send back and forth the data used by the app. This is relatively minimal in terms of networking, though FaceTime requires a few more ports than other functions. These ports are:
- 80 (TCP)
- 443 (TCP)
- Ports 3478 Through 3497 (UDP)
- 5223 (TCP)
- Ports 16384 Through 16387 (UDP)
- Ports 16393 Through 16402 (UDP)
The ports that are done in multiple, which are the many UDP ports, are going to be specific to FaceTime in this situation. The TCP ports 80, 443, and 5223, are also used by iMessage, so when you enable your network for FaceTime you are already going to be enabling it work with iMessage as well.
To have these set you, or the proper network administrator, need to alter the configuration on your router. Since you are running a video based app you may need a few additional ports for the video, but this depends specifically on your NAT configuration and not on the basics needed by FaceTime. You router itself could interfere with FaceTime through Port Mapping, SIP dropping, or dynamic opening of media ports, so you will need to discuss these issues with your network administrator if you are still having issues with FaceTime from behind your firewall.