I recently tried to use my iPhone 4S with iOS 6 to control my iTunes 10.7 on my Macbook Pro. This used to work but the official Apple Remote App did not successfully connect to iTunes anymore.
I followed the knowledge base article and tried to reset all remote settings in iTunes, as well as controlling my wireless network settings. After several unsuccessful tries to pair both machines, I tried to switch my Macbook to LAN connectivity instead of WLAN. And this was the first clue, that the problems must have something to do with my network settings, as I could not pair my iPhone with iTunes anymore.
The key to success was to restart my WLAN router (AVM Fritz!Box 3270). Devices from AVM are known for their problems with Bonjour’s UDP Multicast packets. They are sometimes blocked when the router is running for too long without reboot. So restarting helped me a lot, because after this I could pair iPhone and iTunes again and could start controlling my Macbook’s iTunes again 🙂