I replaced an old router with a Linksys WRT610N. Everything works great, except I can no longer connect iTunes 9 on my Mac (running 10.6) to the Apple TV since installing the new router (the old router was a Linksys as well with nothing special configured).
I can ping the Apple TV by IP address and ssh into it. The Apple TV can get onto the internet fine and can also connect fine to my NAS (via smb). I've gone through the standard connect process and after typing the PIN into iTunes, iTunes says it's unable to connect, though it seems to be able to briefly see the Apple TV, since it is listed under devices with a "setup this device" next to it.
My firewall is disabled on the Mac and there isn't anything special about the router.
One thing I find odd -- since upgrading the router, I can no longer just ping "appletv.local" from the Mac -- the name doesn't exist. Is it possible the router is blocking some ports on my local machines?