4 ms·

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

54 points by pmikal 16y ago

jallmann 16y 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 16y 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 http://tools.ietf.org/html/draft-lee-sip-dns-sd-uri-03 (ignore the stuff about mDNS and substitute Wide-area Bonjour)
patrickaljord 16y ago
Why is "unencrypted" considered a good thing? I find it kind of scary especially for a video conference app.
- jallmann 16y ago
  Your phone calls aren't point-to-point encrypted, either.
  - eli 16y 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 16y ago
      GSM supports optional encryption, but there's no notification to the user whether a given call is encrypted.
      - eli 16y 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 16y 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 16y ago
      I'm pretty sure those are usually leaked, not intercepted.
  - deleted 16y ago
    [deleted]
- ynniv 16y 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!
- mattparcher 16y 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 16y ago
Does anyone think they're trying to figure out IPv6 to make this work over 3G?
- wmf 16y ago
  What does one have to do with the other?
yesbabyyes 16y 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.
pat2man 16y ago
Its actually a little more complicated than that: http://www.packetstan.com/2010/07/special-look-face-time-part-3-call.html http://www.packetstan.com/2010/07/special-look-face-time-par...
michaelbuckbee 16y 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 16y 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 http://news.cnet.com/8301-13579_3-20008289-37.html

54 points by pmikal 16y 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 16y 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 http://tools.ietf.org/html/draft-lee-sip-dns-sd-uri-03 (ignore the stuff about mDNS and substitute Wide-area Bonjour)

patrickaljord 16y ago

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

jallmann 16y ago
Your phone calls aren't point-to-point encrypted, either.
- eli 16y 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 16y ago
    GSM supports optional encryption, but there's no notification to the user whether a given call is encrypted.
    - eli 16y 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 16y 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 16y ago
    I'm pretty sure those are usually leaked, not intercepted.
- deleted 16y ago
  [deleted]
ynniv 16y 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!
mattparcher 16y 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 16y ago

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

wmf 16y ago
What does one have to do with the other?

yesbabyyes 16y 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.

pat2man 16y ago

Its actually a little more complicated than that: http://www.packetstan.com/2010/07/special-look-face-time-part-3-call.html http://www.packetstan.com/2010/07/special-look-face-time-par...

michaelbuckbee 16y 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 16y 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 http://news.cnet.com/8301-13579_3-20008289-37.html