Ethernet and tethering

Mac does not detect a USB or Thunderbolt Ethernet adapter

A USB or Thunderbolt Ethernet adapter must appear as a hardware port and as a network service. Find which one is missing, then add it.

Applies to: macOS 13 Ventura and later for the System Settings steps. networksetup is in all current macOS versions.Checked: 29 October 2026

Symptoms

  • The adapter is connected, but Network settings does not show it.
  • The adapter shows Not Connected, although the cable goes to the router.
  • The adapter worked on another port or another Mac.

Likely causes

  • The cable or port. A damaged cable or a loose connector stops the link.
  • A hub or dock. A hub can give too little power or bandwidth, or it can have a fault.
  • No network service. macOS can see the hardware but have no network service for it.
  • The device at the other end. The router or switch port can be off or have a fault.

How to check

  1. List the hardware ports that macOS knows. Look for the adapter by its name.

    networksetup -listallhardwareports

    Output Blocks of Hardware Port, Device (for example en5) and Ethernet Address.

  2. List the network services. An asterisk means that a service is inactive.

    networksetup -listnetworkserviceorder

  3. Look at the state of the device that the first command gave you. Replace en5 with that device.

    ifconfig en5

    Output A status: line that is active or inactive, and a media: line.

  4. Open System Information from Applications > Utilities. Look for the adapter in the USB or Thunderbolt section.

How to fix it

  1. Make sure that the Ethernet cable is not damaged. Connect it firmly at both ends.

  2. Connect the adapter directly to a port on the Mac, not through a hub.

  3. Choose Apple menu > System Settings > Network. Look for a service with the adapter's name.

  4. If there is no service, click the Action pop-up menu and choose Add Service. Choose the adapter as the Interface. Click Create.

  5. Or let macOS find new hardware and make a default service for it.

    sudo networksetup -detectnewhardware

    Needs an administrator password.

  6. Shut down the Mac. Turn off the router or switch, wait a few minutes, then turn it on.

  7. Start the Mac again when the router or switch is ready.

With Kilobat

  1. See the counters of physical and VPN interfaces separately.

    kilobat interfaces --json

  2. Find which layer fails when the adapter is up but the internet does not work.

    kilobat diagnose

Questions

Does the adapter need a driver?

Read the instructions from the adapter's maker. If the maker supplies a driver for macOS, follow those instructions.

The service is there, but it shows no IP address. What next?

Make sure that the router gives addresses. See Mac has a self-assigned IP address and Renew the DHCP lease on a Mac.

Sources

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with man <name> in Terminal.