Lenovo Thunderbold 3 dock not working

Thunderbolt 3 dock – no network

I have a Lenovo Laptop P52s, connected to a Lenovo Thunderbolt 3 dock. Everything, LAN, video, USB keyboard, …, was working under Windows 10, but after installing Ubuntu 24.04 LTS the keyboard and LAN had problems.

Symptoms

• A Lenovo laptop works partially, forwards the image to the DisplayPort, but not LAN nor keyboard.
• The dock works perfectly on another Lenovo laptop with Ubuntu 24.04 connected to the Thunderbolt port, forwarding the DisplayPort, LAN, keyboard, power delivery.
• All drivers and firmware up-to-date

Solution

There is a setting in Ubuntu 24.04 LTS to allow the dock to connect the LAN to the computer. It’s under Ubuntu’s Settings / Privacy & security / Thunderbolt where I clicked “Allow thunderbolt” and it now works!

Note

After upgrading the system packages the dock may need to be authorized again.