All -
The solution:
There's definitely some misleading information in this thread, but I will try to help because I seem to be having similar issues and just stumbled upon a fix.
First, if windows firewall is off (and assuming you have no other software that's blocking Apple MAC addresses or IPs like Peerblock), then there's no need to play with the firewall.
Second, the only two services that we should be concerned about are Bonjour and Apple Mobile Device. No other service is really relevant to this discussion.
Finally, router/NAT settings shouldn't be afftecting Wifi sync.
Now, what seemed to fix the issue for me was to disable IPv6 on my NIC. This wasn't an issue since I'm on a desktop on an internal network and all internal addressing is done in v4. Bonjour, it seems, pukes when trying to resolve a v6 address when IPv6 is enabled in your TCP/IP stack.
Trying turning IPv6 off, restarting, and giving it a whirl.
On my end, once done, Airport express popped back up and devices were able to sync. Hopefully it's not just a fluke, but give it a shot and see if that helps!!
My original situation:
iPhone 4, iPad 2 were discovered by iTunes 10.5 x64. Airport Express was NOT discovered. Airport Base Station Agent WAS able to connect to the Airport hence some confusion on my end. I concluded from this that the issue was likely with Bonjour.
Event viewier had this to say about the Bonjour Service: Client application bug: DNSServiceResolve(e0:f8:47:df:31:08@fe80::e2f8:47ff:fedf:3108._apple-mobdev._tc p.local.) active for over two minutes. This places considerable burden on the network.
That seems to indicate that Bonjour is attempting to resolve an IPv6 DNS server and not getting a response, thus perhaps causing it to behave strangely or to crash??
After disabling v6 on the NIC and rebooting, things seem to have cleared up. At least for now....
Good luck,
Andrew
http://curatedamerica.wordpress.com