IMPORTANT: AirPlay icon on iPad over WiFi - RESOLVED

Question

Hi,
RESOLVED
The situation was:
- a new Apple TV
- a local network with an Ethernet/WiFi router (in my case, ASUS)
- Apple TV is connected over WiFi
- Macs are connected via Ethernet/wired connection
- iPads are connected over WiFi
I have set up Apple TV, it successfully connected to the WiFi network with WPA2 and I did successfully entered it into the MAC-filtered access list on the router for added security.
Mac OS X 10.8 (Ethernet) showed up the AirPlay mirroring option immediately. On iPads EVERYTHING failed:
- turning WiFi on;
- rebooting the iPad;
- resetting the iPad;
- rebooting all devices on the network, including the Apple TV and the router.
The icon still did not appear both in apps on the iPad and in the Recent Apps pane in the bottom.
The solution which resolved my case:
DISABLE AP ISOLATION in wireless network settings on the router and reboot it to apply changes.
This option was hidden under "Set AP isolated" in my case.
After disabling it, iPads started working normally, connections are stable, AirPlay icon is displayed correctly on all iPads when Apple TV is on.
For those interested, this is WHY this option affects:
"Enabling AP Isolation on the router isolates all the wireless devices that use your network, so that each device can communicate with the router but not with each other. The AP isolation function effectively creates a distinct virtual network for each wireless device that connects to the router. Isolating the wireless devices from each other stops an unauthorized user from manipulating the network connection to hack into a connected computer or mobile device."
Would be great if Apple could add this to Wireless Troubleshooting guide or AirPlay troubleshooting guide!
Hope this will save you a lot of excitement with great Apple products!
Best regards,
Godhell

Answer 1

I've checked your model - it doesn't seem to have the ability to isolate wireless clients - it's not written anywhere at least.
For what could help to understand the cause, I'd check the ARP table on the router (go to Wireless/Station list) for the existence of MAC addresses for both the Apple TV and your iPad.
I'd make a wired connection of any Mac to the router just for the test - if it works, the problem is most likely that the router does have AP isolation - and enabled by default, which you can't change with standard firmware.
In this case, I'd make a little research on whether there are any custom firmware releases (like dd-wrt) for your model and whether they can be flashed (usually it's easy) - they _may_ provide access to the option of disabling AP isolation if it's really there but hidden from common users.
Other things I'd check:
- are all devices on DHCP?
- DHCP lease expires?
- try to assign addresses manually to eliminate any DHCP address distribution issues
- check the MTU in LAN settings - if you've got a non-standard value (certain Internet providers like to complicate things) - could be a problem for certain network services in case of a mismatch
Hope that could help,
Best regards,
Godhell