Wireshark: Facetime on Iphone 4: Vanilla unencrypted STUN and SIP

jallmann 15 years ago |

Hopefully once Apple "opens" up facetime, they will also enable calls outside the Facetime network. Otherwise the who's and what's of connecting to their registrar will probably be no better than the App Store situation today (eg, I'm sure gateways will be forbidden).

edit: Although the identifying info from those screenshots is scrubbed, the comments say the R-URI is basically user@ip:port. This is interesting: there's no SIP proxy in between. No wonder it only works over wifi.

andrewtj 15 years ago | |

Although the identifying info from those screenshots is scrubbed, the comments say the R-URI is basically user@ip:port. This is interesting: there's no SIP proxy in between.

Unfortunately I see "Bandwidth Limit Exceeded" when I go to that page but your comment makes me wonder whether they are doing SIP URI discovery via DNS-SD[1] given their penchant for DNS-SD.

[1] http://tools.ietf.org/html/draft-lee-sip-dns-sd-uri-03 (ignore the stuff about mDNS and substitute Wide-area Bonjour)

pat2man 15 years ago |

Its actually a little more complicated than that:

http://www.packetstan.com/2010/07/special-look-face-time-par...

michaelbuckbee 15 years ago |

Since Facetime is running SIP over WiFi, does AT&T still charge you minutes for a Facetime call or is that only for the non-facetime portion of the phonecall?

mattparcher 15 years ago | |

Apparently no:

“The voice call ends as soon as the FaceTime call connects... the FaceTime call is over Wi-Fi so does not use carrier minutes.”

http://news.cnet.com/8301-13579_3-20008289-37.html

yesbabyyes 15 years ago |

This is cool. This, Google Voice and Sipdroid on my Desire (which lets you route all calls, automatically, to the SIP provider of you choice, either on Wi-Fi only or 3G as well) makes me feel good about the future of telephony.

patrickaljord 15 years ago |

Why is "unencrypted" considered a good thing? I find it kind of scary especially for a video conference app.

ynniv 15 years ago | |

It's much easier to add encryption to an unencrypted channel than it is to interoperate with a fully encrypted one. As a user you might be more interested in encryption as soon as possible, but to the average HN reader an unencrypted standards-based stack is good news!

jallmann 15 years ago | |

Your phone calls aren't point-to-point encrypted, either.

eli 15 years ago | | |

No, not end-to-end, but they are encrypted between your phone and the cell tower.

It's considerably more secure than an open wifi network.

sp332 15 years ago | | |

GSM supports optional encryption, but there's no notification to the user whether a given call is encrypted.

eli 15 years ago | | |

Yes, but I'm pretty sure all US carriers use it all the time

(Though it's true that this opens you up to a potential MITM attack by a well equipped adversary, it's still a far cry from an open wifi network)

drewcrawford 15 years ago | | |

Remember all those scandals where politicians sent sexy texts to people they weren't supposed to? Video looks a lot better on the evening news.

Cue first FaceTime scandal in 3, 2...

eli 15 years ago | | |

I'm pretty sure those are usually leaked, not intercepted.

mattparcher 15 years ago | |

I may be missing something, but isn’t he saying that the FaceTime call, once initiated by a traditional phone call, is encrypted?

“Only the call part is Vanilla SIP. The procedure for registering a Facetime user into their servers etc. is all non-SIP, encrypted/ciphered.”

gsiener 15 years ago |

Does anyone think they're trying to figure out IPv6 to make this work over 3G?

wmf 15 years ago | |

What does one have to do with the other?