This is a short story of using one device to route around another, misbehaving, device, and trying very hard to not let technology get in the way of what matters.
In my house, we listen to music streamed to an AirPort Express connected to the stereo system in our living room. My wife's first-generation MacBook currently contains our iTunes library, and it's from that machine that we play most music.
Unfortunately, upgrading the MacBook to Mac OS X 10.5.6 threw a wrench into the works. For no good reason, iTunes reported that it couldn't stream to the AirPort Express, citing error number "-3256". I didn't have the same problem on my MacBook Pro, which shared the same settings and operating system version. A quick trip to Apple's support Web site revealed "Error -3256 or -15000 when streaming to AirPort Express base stations using iTunes," explaining that Leopard's firewall was likely blocking UDP traffic.
I walked through the steps provided by Apple, confirmed that the settings were correct in the Security preference pane (they didn't require a change), and closed System Preferences. Same error. I changed the Firewall setting from "Set access for specific services and applications" to "Allow all incoming connections." The error continued to appear. (See the update at the bottom of the article for a possible solution suggested by a TidBITS reader.)
Plenty of other troubleshooting steps stretched out in front of me: sign in as another user, reboot the AirPort Express and the AirPort Extreme to which it's connected, or hurl invective at an old Dell laptop as a form of technology sacrifice. But it was also early evening on Christmas Eve, and after working for most of the day I wanted to spend time with my family and listen to holiday music, not bury my head in a computer.
Abandoning the AirPort Express for the time being, I turned to another device that could stream audio: my Apple TV. I still haven't purchased a high-definition television, so the Apple TV was connected to an LCD display upstairs in my office (see "DRM Foils iTunes Movie Rentals for Some Apple TV Owners," 2008-02-20).
I brought it downstairs, connected audio cables between it and our stereo receiver, and powered it up. It was already set to connect to my wireless network, so within a few minutes it was ready to go. (I did haul my LCD display down in case I needed to use the Apple TV's remote to configure the network connection, but I ended up not needing it.)
The Apple TV can act as a source for remote speakers, just like the AirPort Express, but the MacBook still registered the same error when trying to stream music from iTunes to the Apple TV. However, it had no trouble syncing the music library between the two machines, which meant that our holiday playlists were already present on the Apple TV's hard disk.
(A couple of readers have pointed out that I didn't even need to relocate the Apple TV. The latest software update added the capability to stream music from the Apple TV to the AirPort Express. However, at the time I didn't know if the AirPort Express was part of the problem, and I was trying to come up with the most direct, least time-sucking solution.)
To control the Apple TV without a display attached, I launched Apple's Remote application on my iPhone. It was already set up to control the Apple TV, so I was able to start playing music with just a few taps.
Sure, I feel a little guilty that my Apple TV is currently relegated to music-only status, but I also see this move as part of its slow but eventual march to the living room anyway. When I do finally buy an HDTV, the Apple TV will already be in position and connected to the stereo.
Our music is back, and I didn't spend Christmas troubleshooting.
[Update: TidBITS reader Will Mayall suggested I turn off IPv6 networking to solve the problem on the MacBook, and it seems to have done the trick. In the Network preference pane, click the Advanced button, then click the TCP/IP tab. In the Configure IPv6 pop-up menu, choose Off.]