Recently, I got my Apple TV back from repair. After setting up the wireless network connection and trying to connect it to the shared iTunes library on my Mac I was expecting it to show up in iTunes so I could enter the key to pair both devices. Apple TV usually shows up within seconds in iTunes. Not this time! No matter what I did, it just wouldn’t show up. I rebooted the Mac a dozen times, made sure the Mac OS X firewall is disabled, rebooted Apple TV, set Apple TV back to factory settings, restored it to the initial firmware release, upgraded the firmware again, ran it in diagnostics mode, moved it closer to my Wi-Fi access point, made sure the checkbox in iTunes was set to discover Apple TVs, made sure my iTunes library was shared on the local network… all to no avail.
After three hours of investigation I found out that one reason was a setting called Block wireless bridging I (stupidly) activated the other day on my router/access point without precisely knowing what it does :-) I thought it would do something else but according to the manual, this is what it does: it isolates all wireless clients on your network from each other. Wired clients will be seen and internet access works from Wi-Fi clients but you’re unable to see other wireless network clients on the same local network.
But guess what, even after fixing this issue, Apple TV still wouldn’t show up in iTunes. I had a look at my Mac’s log files and found some mDNSresponder warnings in it. I installed a Bonjour browser and sure enough, Apple TV didn’t show up in the list of devices even though I was able to ping it. So it seemed that there was some kind of Bonjour related problem on my Mac. I then downloaded the Bonjour conformance test:
Ran it with sudo ./BonjourConformanceTest -I en0 -L p -M hu
(It will ask you for your root password)
and while the conformance test was still running, Apple TV suddenly showed up in iTunes and the Bonjour browser! I entered the 5-digit code displayed on Apple TV to pair it and now it all works as expected. Apple TV shows up in iTunes every time. Somehow the conformance test fixed whatever was wrong with Bonjour on my Mac.