Update 2009/10/27: It looks like I was wrong. Apparently when iTunes launches it selects the highest-priority available IP (normally Ethernet for me), and Apple TV sync & AirTunes use that IP. I don't think Apple TV pairing is actually relevant.

So the bug is that if the preferred IP is offline, iTunes keeps telling Apple TVs & AirPort Express units to connect to that unavailable IP, rather than switching to an IP that is online. My workaround if I want to stream wirelessly is to quit iTunes, unplug Ethernet, and relaunch iTunes. Then I'm good until I reboot, because I don't quit iTunes, log out, or reboot under normal circumstances.


Note that this looks like a design flaw, rather than an implementation bug. It appears to do exactly what it was programmed to do, but the design wasn't sufficiently thought out before implementation.

<rdar://7329267> = http://openradar.appspot.com/radar?id=100401

I'm glad I have a workaround, because I don't expect Apple to change the nitty-gritty details of iTunes' DAAP server or Apple TV / AirTunes clients soon...


See also #5908799: AppleTV connects to AirPort instead of Ethernet.

This has been broken since I bought an Apple TV in May of last year. I was told that one Time Capsule firmware update would help, but it did not. Today I did some more testing, and believe I know what's wrong.

Our home network is 10.n.n.0/24, and I routinely connect my MBP to it via gigabit Ethernet to transfer large files (the Apple TV is connected via 100mbps Ethernet). In addition, the MBP is always connected to the same subnet via 802.11n.

I have been able to stream music to the Apple TV and an AirPort Express when Ethernet was connected, but generally unable to sync when Ethernet was disconnected -- the Apple TV only appeared under DEVICES on the right, and the AirTunes pop-up in the lower right, when Ethernet was available.

My wife's MacBook, which only uses AirPort, is able to stream, and my iPhone is able to use Remote.app across the wireless network.

Today I did some more testing, and believe I know what's wrong. When I first got the Apple TV, iTunes failed to complete the initial copy over AirPort, despite having an Ethernet connection available (and specified as preferred in System Preferences:Network). I believe I then unpaired, plugged Ethernet into my MBP, and re-paired. Since then, Apple TV sync and AirTunes have only run over Ethernet (survivable, as it's much faster), but I hadn't realized the pairing was preventing me from streaming audio over AirPort.

http://www.extrapepperoni.com/post/2008/05/03/apple-tv-in-the-house/

Tonight I unpaired the Apple TV, disconnected Ethernet, and repaired it to the MBP (AirPort IP address). I am now streaming music to the Apple TV and refilling its hard drive (which was cleared when I unpaired) very slowly via AirPort. These should really run over gigabit Ethernet, which would be much faster, but at least streaming should work with or without Ethernet now.

Bug #1: Apple TV sync always runs over the Mac's interface (IP) which iTunes was using when it was paired. It should run over the best available interface (order of preference for interfaces is configured System Preferences:Network). Apparently the Apple TV connects to iTunes as a DAAP server, so it needs more intelligence about how it finds iTunes. This is particularly annoying when initially synching over AirPort, which is slow and may not complete (see blog post above). It is particularly important for users with erratic AirPort reception but Ethernet available, as their only options are unnecessary drop-outs (AirPort), or intermittent availability (Ethernet).

Bug #2: Apple TV sync breaks when the originally configured interface is unavailable, even when the Apple TV could communicate with iTunes via another IP.

Bug #3: AirTunes streaming to Apple TV only works over the paired IP. I don't understand why this is so, but that's my observation.

Bug #4: AirTunes streaming to AirPort Express units also requires the IP paired with Apple TV. I have NO IDEA why, but again this is my experience.

Bug #5: There is no indication of this requirement during the pairing process.


Update: How does this work for Apple TV users with unstable DHCP IPs (mine are locked by MAC in the Time Capsule)?