Troubleshooting Your Ethernet or Thunderbolt Connection

When the Thunderbolt or Ethernet cable connected between your devices fails to connect the Luna apps, there are a few things you'll need to check to make sure the connection is set up properly. The Thunderbolt or Ethernet connection must be established on your devices before launching the Luna apps.

The Thunderbolt or Ethernet cable must be plugged in before launching the Luna app. Please allow up to 60 seconds for your devices to register the connection before launching the apps.

Changing the Connection Filter so your devices connect via Ethernet or Thunderbolt Only

Luna should connect automatically if it detects an active Ethernet or Thunderbolt connection between your devices. If this connection isn't registered through the apps, you can adjust Luna's settings so that Luna will only connect over an Ethernet or a Thunderbolt connection, instead of Wi-Fi.

Note: While Thunderbolt connections work in PC-to-Mac mode, we recommend connecting via Ethernet when possible, as Thunderbolt cables are not always the most reliable connection type when used with a Windows device. This is due to how Windows behaves with Thunderbolt cables.

Mac-to-Mac Connection Filter:

In your Mac's top menu bar, click on Luna Display then Settings. In the Mac-to-Mac tab, change "Allow any network interface (default)" to your preferred connection method: Connect via Wi-Fi only, Connect via Ethernet only, or Connect via Thunderbolt only.

PC-to-Mac Connection Filter:

In your PC's menu bar, click on Luna Display then Preferences. In the Connectivity tab, change "Allow any network interface (default)" to your preferred connection method: Connect via Wi-Fi only, Connect via Ethernet only, or Connect via Thunderbolt only.

How to check that Thunderbolt or Ethernet Bridge is connected on macOS

The Thunderbolt or Ethernet Bridge is a network interface that allows data transfer between two devices via a Thunderbolt or Ethernet cable. This should be established once the cable is connected between the two devices. To check that the Thunderbolt or Ethernet Bridge has been properly set up:

Connect your primary and secondary computer via the Ethernet or Thunderbolt cable. Plug one end of the cable into your primary device and the other end of the cable into your secondary device.
Go to the Apple menu on both your primary and secondary device > System Preferences > Network
You should see the connection types listed on the left-side menu panel. If using a Thunderbolt cable, you'll look for Thunderbolt Bridge. If using an Ethernet cable, you'll look for USB Ethernet or USB/LAN.
Once the cable is connected between both devices, the connection status on the left-side menu panel should change to a yellow or green dot and be labeled as "Self-Assigned IP" or "Connected".

If the Ethernet or Thunderbolt Bridge says "Not Connected" or has a red dot, this means that your devices are not registering the cabled connection. If it states "Not Connected", there are a few steps you can try to get it working:

Try readjusting the cable between your devices by unplugging them and plugging them back in. Make sure the cable is snuggly fit into the port.
Try another Thunderbolt or Ethernet cable, as the cable you're using could be faulty.
In the left side menu, select Thunderbolt or Ethernet Bridge and ensure that Configure IPv4 is set to "Using DHCP."
Power down and reboot both your primary and secondary devices. Check to see that the Thunderbolt or Ethernet Bridge is now connected.
Contact Apple Support for further guidance.

If the Ethernet or Thunderbolt Bridge says "Connected" or "Self-Assigned IP" and shows a green or yellow dot, this means that your devices are registering the cabled connection. If Luna Display still isn't connecting via Ethernet or Thunderbolt, we recommend completing a ping test to make sure your devices can communicate through the cabled connection.

More Ethernet Connection Troubleshooting

Make sure both ends of the Ethernet cable are fully connected to each Mac, router, or access point.
Restart your Macs, router, or modem.
Create or switch to a new network location on your Mac.

For more help, check out Apple's support article for troubleshooting an Ethernet connection on a Mac.

More Thunderbolt Connection Troubleshooting

Make sure both ends of the Thunderbolt cable are fully connected to each Mac, router, or access point.
Ensure your cable is Thunderbolt-compatible.
Restart your Macs, router, or modem.

For more help, check out Apple's support article for troubleshooting a Thunderbolt connection on a Mac.

How to complete a ping test using a Thunderbolt or Ethernet connection in macOS

Open the Luna primary application on your primary Mac. Change the connection filter to Allow any network interface (default). You can find this by going to Luna Settings > Mac-to-Mac
Next, quit Luna Display on your primary device and Luna Secondary on your secondary device
Open the Network Preferences on your primary and secondary Mac devices
Check under the Thunderbolt Bridge (for a Thunderbolt connection) or USB/LAN (for an Ethernet connection) and make sure it says "Connected" or "Self-Assigned IP" on both devices
Open the Apple Network Preferences on your primary and secondary Mac devices and note the IP address for the Ethernet or Thunderbolt connection
Complete a Ping Test to make sure your devices can communicate via Ethernet or Thunderbolt
To complete the ping test, open Terminal on your primary device (instructions to find this here: Open/Quit Terminal) and run "ping enter the IP address that you gathered from the secondary device".
Next, open Terminal on your secondary device (instructions to find this here: Open/Quit Terminal) and run "ping enter the IP address that you gathered from the primary device"
If the ping communication is successful, it will look similar to this ping test result:
If the ping communication is unsuccessful, it will look similar to this ping test result:
If the ping communication is successful, but your devices do not connect, please reach out to our Customer Experience team for further assistance.

If the ping communication is unsuccessful, please try completing the ping test one more time or resetting the cabled connection.

Can adapters be used for wired connections between devices?

How do I use a USB, Ethernet, or Thunderbolt connection?

Yes, adapters can be used for wired connections, such as Thunderbolt or Ethernet cables. This is recommended if your devices have incompatible port types. Using adapters for wired connections is different than using an adapter to plug your Luna unit into your computer. You will still need to plug the Luna Display hardware directly into your Mac or PC, even if you are using a wired connection.

For example, let's say you are using a 2015 iMac as a secondary display for your 2021 MacBook Pro and would like to use a Thunderbolt cable to connect your devices (instead of using WiFi). The 2015 iMac has Thunderbolt 2 ports (mini DisplayPort), while the 2021 MacBook Pro has Thunderbolt 4 ports (USB-C). You will need an adapter in order to use a Thunderbolt cable between these devices. In this instance, we would recommend using a Thunderbolt 3 to Thunderbolt 2 adapter with a Thunderbolt 2 cable.

In another example, using the same devices as above, let's say you'd rather use an Ethernet connection between these devices. The 2021 MacBook Pro does not have an Ethernet port, while the 2015 iMac does. You would need an Ethernet to USB-C adapter in order to utilize an Ethernet connection between these two devices.

While we do not recommend plugging the Luna hardware unit into any adapters or docks, using an adapter or dock for your Ethernet or Thunderbolt cable should not affect your connection through Luna.