Apple have done nothing, they just ignore this issue. Home sharing has not worked for me since the upgrade to iTunes 11. Some People are buying new Routers changing their network configurations but to no avail. I have spoken with apple technicians for over 20 hours ( telephone). They would not accept that the issue was due to iTunes. Everything was tried with my network but the problem was never found. I made my network as simple as possible, because Apple told me that my network was to complicated. My simple network was a Cisco 3010 modem from my cable TV company, Apple AirPort Extreme and the ATV2. With this setup I could play one maybe 2 songs then it would lose the connection. I gave up in the end and told Apple that I was not interested in their help anymore. I was told that I could ring again anytime and they would continue to troubleshoot the problem.
Everything else works on the ATV2 Netflix, podcasts in fact all of the apps. I only use my ATV2 for Netflix now. I use my Synology Diskstation to stream my music and videos from my computer to my TV,
. I can also use DNLA to stream over my network without any problems, but homesharing it's a JOKE!
Home sharing has not worked for me since the upgrade to iTunes 11.
I had this happen once on an iTunes upgrade - not sure why but iTS upgrades DO seem to confuse ATVs occassionally.
If you have another home share device, try connecting to that first.
One other thing that worked was a total reset. Then I followed Apple's instructions as if I was setting up for the first time. The counterintuitive part was that iTunes needs NOT running when you first enter info in ATV. THEN atv gives you a code to enter. At that point you open iTunes. (truly bass ackwards). Don't recall if I tried, disabling then enabling Home Sharing on the computer.
Anyway, don't dismay. iTunes 11 DOES work with ATV.
You should also look at the following article which discusses port settings for iTunes, ATV etc.: