For the best performance using Duet, connect your Duet-enabled Mac and Windows devices via Thunderbolt cables. Duet Over Thunderbolt is a powerful feature that provides multiple benefits versus standard network connections:
Thunderbolt allows incredible transmission speeds - at least 10Gb/s.
Thunderbolt has virtually no lag - less than 1ms for Mac-to-Mac connections.
Thunderbolt keeps your video stream off of your network. This is especially valuable for 4k+ streams due to the high bandwidth needed.
You'll need a Thunderbolt cable and two computers with compatible Thunderbolt ports. At least one of these must be a Mac, and the other may be Windows or Mac. Make sure that the cable you have is compatible with both ports. Depending on your device’s age, it may support only the original Thunderbolt, Thunderbolt 2, Thunderbolt 3, or even Thunderbolt 4. Check your device's technical specifications to find out which Thunderbolt cable type it supports.
Thunderbolt 3 and 4 cables are typically USB-C, but not all USB-C ports on your device necessarily support Thunderbolt; look for a lightning icon next to the port.
The configuration instructions for Mac-to-Mac and Mac-to-Windows differ slightly from here. These steps are only needed for the first connection. After that, simply connect the Thunderbolt cable and Duet will use it automatically.
For the Mac-to-Windows guide, please scroll further down. For the Mac-to-Mac guide, continue below.
Close Duet on both systems.
Plug one end of the cable into each Mac, making sure you choose a Thunderbolt-capable port. You can plug the cable in while the Mac is running; the cable should be detected and activated by macOS automatically.
Once the two Macs are connected by the Thunderbolt cable, open the macOS System Preferences and choose Network on the sidebar.
The "Thunderbolt Bridge" is the connection over the Thunderbolt cable. If you do not see this, macOS has not detected your Thunderbolt connection, and you may need to change the cable or the port in which it is inserted.
By default, the Thunderbolt Bridge will come up unconfigured, with a red dot. After a short delay (once both Macs are connected), macOS will assign it a "Self-Assigned IP", and display a yellow dot. The Thunderbolt cable is usable at this point, and Duet will use it automatically.
Open Duet on both systems and start connecting - you're ready to go!
Optional: If desired, you can set a static IP address for the Thunderbolt Bridge. If you do this it must be done on both Macs, and they must have different IP addresses that are in the same subnet. To do so, please scroll down to step 2 (Set the Thunderbolt Bridge on Mac to Manual IP of the Mac-to-Windows guide below. Once both Macs have IP addresses with corresponding subnet masks, the dot should appear green.
Enable internet sharing on the Mac. Note: This step is only needed when connecting to a Windows 10 device. If you have Windows 11 on your other device, you may skip to step 2.
a. Open System Settings, click General in the sidebar, then click Sharing on the right.
b. Click the Info button next to Internet Sharing.
c. Click the “Share your connection from” pop-up menu, then choose the internet connection you want to share. For example, if you’re connected to the internet over Ethernet, choose Ethernet.
d. In the “To computers using” list, select Thunderbolt Bridge.
e. Click done, then turn on the toggle for internet sharing.
Set the Thunderbolt Bridge on Mac to Manual IP.
a. Open System Settings, click Network in the sidebar, then click Thunderbolt Bridge on the right.
b. Open the “Details…” menu, then click TCP/IP on the left.
c. Toggle “Configure IPv4” to “Manually”.
d. You will need to fill in both the "IP Address" and "Subnet Mask" fields. The address should not be in the same subnet as any of the other networks listed in the Network panel of System Preferences. A good choice for most networks is 10.10.10.1 and 255.255.255.0.
e. Hit ok to confirm.
Plug in the Thunderbolt cable and wait for the connection to fully initialize.
Set a manual IP address for the Windows Thunderbolt Bridge adapter. Use the same subnet mask as the Mac device and another IP address within that range. For example, 10.10.10.2 and 255.255.255.0 would match with the above recommendation. Note: Each Thunderbolt port on your PC is treated as a separate network adapter by Windows, so you’ll need to repeat this step for each port you plan to use in the future.
a. Open the Network and Sharing center, then click “Change adapter properties”.
b. Right click on the thunderbolt bridge and click Properties.
c. Make sure the box is checked for “Internet Protocol Version 4 TCP/IPv4”.
d. Change the properties of TCP/IPv4 to use another IP on the subnet such as 10.10.10.2 and set the subnet to 255.255.255.0.
Unplug the Thunderbolt cable, and restart the Windows machine.
Once you are logged back in to Windows, plug in the Thunderbolt cable and wait for the connection to fully initialize.
At this stage, Duet over Thunderbolt should be ready to go! Once you start a connection from either side, you should see TB and a lightning icon ⚡ in the bottom left corner of the Mac UI. If not, you may need to restart Duet on both devices to register the new IPs.
To check if the Thunderbolt Bridge is working outside of Duet, open a command line terminal (such as Terminal.app or cmd). Then use the 'ping' command with the Thunderbolt Bridge IP address of the other computer. For example, ping -c 5 10.10.10.1. If you are testing from Mac to Windows, you will need to allow ping through your Windows firewall.
If you see 0% packet loss as shown above, your connection is working correctly. If you see 'Request timeout for icmp_seq' or more than 0% packet loss, double-check the IP address to ensure it was entered correctly. If the IP matches the one you assigned to the other device’s Thunderbolt Bridge then there is an issue with your connection. If ping is not working in either direction there may be an issue with your Thunderbolt cable, or it may not be plugged in correctly.
Common Issues and Fixes
If you are not seeing the expected performance increase, try restarting the Duet app on both devices after the above ping test is successful. Duet may be using the internet IP address instead of Thunderbolt. If you suspect that is still the case after restarting Duet, contact support.
If the Thunderbolt connection is not recognized by the Windows PC, you may need to update your Thunderbolt drivers or firmware. Consult your manufacturers webpage for this information. Alternatively, try another Thunderbolt cable and double-check your ports.
When establishing the Thunderbolt connection for the first time, Mac or Windows may need to reboot to load new drivers or re-initialize the network adapter. Contact support if you are still experiencing issues after rebooting both devices.
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