Home sharing is not working in apple tv after upgrading apple tv to 4.2.2. I've had apple tv working just fine for some time now and after upgrading, it stop working and prompts me in Apple tv to turn on home sharing in Itunes. It's on.

Question

It asks me, in apple tv when I go to my "Library" to turn on home sharing.  It's on.  When I turn it off and back on I can access my itunes stuff fine for a day or two and then it doesn't work again.  I've tried unplugging appletv, reboot the router (att uverse), and then plug in apple tv again and it doesn't help.  it's still give me the message.  the only thing that works, temporarily, is to turn off home sharing and turn it back on.
I'm using itunes version 10.5.0 on windows 7.  can someone help me with this?   I can't run up and down the stairs all the time.  I have bad knees and other conditions that stop me from doing that.  Please help.
Thanks.
Jim.

Answer 1

Hey all,
I've been having similar problems so I put a packet analyzer on the network to see what's really happening. (Apologies in advance if this post is too techno-babbly...)
Some background:
How do Apple devices find each other over the network?
iTunes with home shaing turned on sends out a message to a special IP address called a multicast (224.0.0.251, in this case.) All your Apple devices listen to this multicast address and respond over that same address. This process applies to iTunes, AppleTV and Apple Remote at least (those are the things I've been testing with.)
How do Apple devices communicate with each other once they're found?
Once they find each other, they establish a Transmission Control Protocol (TCP) communication session. This connection is only between two devices. In this case, iTunes and AppleTV or Apple Remote and AppleTV. The TCP session is how data gets transferred between devices.
The problem:
I captured the protocol traffic between my PC and AppleTV first with the firewall software turned off. In my case, I use Norton 360. What I see is iTunes and AppleTV communicating over the multicast address every 100 seconds. My iTunes usually 'disappears' from AppleTV and the Apple Remotes within about 5 minutes so I left the firewall off for half an hour and everything worked fine. I turned the firewall software back on and then restarted everything. iTunes then did the device discovery and all the devices found each other. Then, after a period of about five minutes of inactivity, the multicast discovery protocol stopped being sent by my PC. Why? I really don't know. From watching the apple protocol's timing, contents and behavior, I see nothing wrong with the implementation. I've done troubleshooting on other location-based multicast protocols for work and have seen some dumb things but Apple's protocol is done correctly and behaves exactly as I would expect.
The solution:
I put a rule into my firewall software explicitly allowing the multicast IP address and also the local subnet that my devices use. I then moved the new firewall rules to the top of the list to ensure that they will be 'hit' before any of the other rules in the list. After that, I left the firewall on and tested for a while then left everything idle for an hour. When I came back, everything still worked. I would suggest that replacing your firewall software won't necessarily help you here. You just need to make sure that the rules for the Apple stuff are put in manually and are at the very top so that another deny rule in the list doesn't trigger before the new permit rules. Hopefully it goes without saying but doing the above leaves your PC completely wide open on the local network so, if you use wireless, please be sure to use encryption on it.
Hope that helps...