Could you explain in detail on how the devices are setup in your network?
McAfee SecurityCenter click on Internet & Network > Configure > Firewall Advanced Options > System Services
Under system services click Add and specify the following:( you may edit the newly created one)
Program name (iTunes Sharing), Inbound TCP/IP ports (3689), Outbound TCP/IP ports (3689), Inbound UDP ports (5353), Outbound UDP ports (5353).
Please keep in mind that I'm not a tech guy, so I'm not sure exactly what you're asking, but I'll try.
My iTunes is on a Dell desktop that runs on XP and is connected directly to a wireless Motorola router. My apple tv is wireless also connecting through the router. When I try to sync the itunes and apple tv, I'm getting an error code to open a communication port 3689.
I hope this is what you need. Please ask if you need more information to diagnose the problem.
Wondering how/if you ever got this fixed... I have the same problem....
This was some time ago, so I don't exactly remember how I did it. I believe I was able to manage network from the McAfee Security Center and somehow allow the appletv. I'm sorry I don't have more info for you.
How many computers you have ?
Is itunes and Apple TV on the same computer ?