I'm running iTunes 11 on my Mac with an old iPod touch (iOS 5) serving as a jukebox and an iPhone 4 (iOS 6.1) as my main device. Both are set up for wireless synching.
When I start iTunes, it finds the iPod and synchs with it wirelessly without trouble, but it doesn't find the iPhone, forcing me to connect it to synch with the dock cable.
If I disable wireless synching for the iPhone in iTunes, synch, re-enable wireless synching and synch again, wireless synching returns and works again.
Until such time as I quit iTunes and restart it.
Why does this keep happening? It can't be a network/firewall problem, because the iPod keeps on synching with the same machine through the same network. Needless to say I'm finding this pretty frustrating, what's the point of wireless synch if you keep having to re-enable it with the dock cable every time you start iTunes?
Best Answer
I've been investigating this problem for a number of years now and I've concluded the following:
Most home wireless/wired routers do not support Multicast-DNS forwarding between wireless and wired network segments.
If both your server (iTunes) device and your client (iPhone/iPad,etc.) are on the same segment (i.e. wireless), then iTunes wireless sync should be more or less stable.
If your server and clients are on different network segments (i.e wireless and wired), you will have mixed success with running a stable wireless sync.
My solution was to buy an enterprise firewall (FortiGate) and create one virtual layer-two segment, encompassing all the wireless and wired interfaces on my home network.
This has stabilised wireless sync.