Although the article below mainly focuses on Wi-Fi connections, there is some information regarding troubleshooting your Ethernet connection:
Apple TV can use either an Ethernet or a Wi-Fi connection. When Ethernet is connected, Apple TV automatically defaults to using that connection.
Verify that your Apple TV is using the latest software by selecting Settings > General > Software Update. If your Apple TV can be updated, install the update and then try the steps again.
Checking your network connection settings. You can view or adjust these by selecting Settings > General > Network on Apple TV:
Restart your Apple TV by selecting Settings > General > Restart.
Try restarting your router and modem by turning it off and then on again.
I hope this information helps ...
Hi, Judy. All of the above did not work. I'll give you a more detailed description of my setup, maybe it will help...
Cable coming in from outside to Cable Modem to Airport Extreme to DLink hub to ATV3. I've hooked up my Macbook pro to the same line of the ATV3 with no problems.
When i hook up the ATV and go to settings, i get this info:
IP Address - yes
Subnet Mask - yes
DNS - n/a
Thanks in advance