MacOS – macbook air: unable to assign static IP on USB ethernet adapter

ethernetmacosNetworkusb

I want to connect to a USRP X310 device via ethernet. The apple USB ethernet adapter is plugged in and is shown by ifconfig:

en3: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=4<VLAN_MTU>
ether 00:f7:XX:XX:XX:XX 
nd6 options=201<PERFORMNUD,DAD>
media: autoselect
status: inactive

However in Network Settings it is shown with a red dot and the following text.

Status: Cable Unplugged

Either the cable for Apple USB Ethernet Adapter is not plugged in or the device at the other end is not responding.

I want to set a static IP as it is stated here. I set the following parameters:

  • Configure IPv4: Manually
  • IP Address: 192.168.10.1
  • Subnet Mask: 255.255.255.0

When I check ifconfig it does not show any changes to before. A ping to 192.168.10.2 returns "Request timeout". So I guess that the IP address is not assigned.

When I connect the mac to the PC which has a static IP of 192.168.10.1 the mac first sets a self-assgined IP of 169.254.145.146. When I set the IP of the mac ethernet adapter to 192.168.10.1 and the two machines are connected, I can ping both machines from the other machine (when firewall is turned off on mac).

Am I missing something? What can I do to assign a static IP to connect to the device? When I connect the device to my PC running Arch, I can set the static IP and ping the device! So I guess that it has something to do with macos or the adapter.

I am running Mojave on a late 2013 MacBook Air and am using a A1277 USB ethernet adapter from apple. The ethernet cable is connected to the port "0" on the USRP X310 device, which is turned on.

Best Answer

Put a small switch between the device and the Mac.

Whatever "device" you're using, it's not bringing up the physical layer (OSI layer 1) and thus, your Mac is not seeing that anything is physically there. That's why you're getting a "Status: Cable Unplugged" error message.

However, when you connect your Mac to a PC, you immediately get a self assigned IP address indicating that not only is a physical connection, but you made it all the way to Layer 3, the network layer. You don't get an IP because there's no DHCP server, but you can now successfully set your desired IP and ping the PC.

A switch will between your device and your Mac will set bring up the link layer allowing you to set the IP.

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