firewall settings for apple tv

From the article linked below:

Firewall security settings

If you use the firewall, make sure the following firewall security options have been set to allow AirPlay Mirroring to work:

1. Choose Apple menu () > System Preferences.
2. Click Security & Privacy, and then click Firewall.
3. Click the lock icon to unlock it if it's locked, then type an administrator name and password.
4. Click Firewall Options.
5. Uncheck (deselect) “Block all incoming connections” checkbox.
6. Select (check) the “Automatically allow signed software to receive incoming connections” checkbox.

AirPlay Mirroring - About