Using LittleSnitch I noticed that Messages (iChat) tries to connect to over udp when I open the audio and video preferences for the application. Apple owns that IP address but does anybody know why it would need to call home?

Little Snitch Dialog

  • It would call home if you have entered any accounts that use Apple's location services. iChat (via AIM) or iMessage would be the reasons I can think of off the top of my head.
    – bmike
    Commented Jan 1, 2014 at 17:20

1 Answer 1


The port is used to "set up Real-Time Transport Protocol (RTP), Real-Time Control Protocol (RTCP)" according to Apple.

According to wiki, "the Real-time Transport Protocol (RTP) defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and web-based push-to-talk features."

Note: iChat became Messages.

Source: http://support.apple.com/kb/TS1629?viewlocale=en_US&locale=en_US

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