A trouble shooting guide for Ethernet port not working.
Hopefully one of these solutions will work for you.
It took eight days to troubleshot the problem and support with the manufactures/developers has been quite dismissive and frustrating. I hope this post can save time for other frustrated souls.
In our case - We have a CalDigit TS3+ with ethernet and an Aukey hub with ethernet that weren't working at all. But, we got them to work and it was a software issue.
This is what we saw. We had no network connection at all when the ethernet cable was connected to the port. If the cable is disconnected we had wifi. This is because primary connection in the system preferences is set to ethernet. You can change the order by going to:System Preference>Network> Click on the gear button next to the "+" and "-" button on the lower left of the panel and select "Set Service Order…"
If you are able to get am IP address from the ethernet card most likely is a software conflict. In our case we could surf with Wifi but not with ethernet connection (this was possible with the wifi as the primary network Service order as explained above)
• Restarting the computer is the first thing to try - FYI with the Silicon M1 chips restarting the computer resets the SMC.
• Make sure the firmware on the hubs you are using is up to date in our case Firmware v44.1
• Make sure the drivers, if needed, are up-to date and they match your OS
• Check if the ethernet port is working in Safe Mode. If it is, it's most likely a software issue and not a hardware issue. If it's hardware, take the computer in for diagnostics. The Apple store should be able to run a diagnostic on the spot it take about an hour, all they have to do is run a software from one of their device while connected to your device. Bring the hub that is giving you trouble with you that way they can see what the issue is.
• Check that any software that uses the ethernet connection is fully disabled and see if you get full network and internet. In our case the VPN software was causing software conflicts. Not sure who is at fault with the software Apple or the software developer. You might need to uninstall the app completely or you might get away with simply quitting if you you have set to start at start-up.
• Try a different cable to connect to the hub.
• If you hub is a thunderbolt 3 hub make sure you are using a Thunderbolt cable and not a USB-C cable. While they look the same work differently.
• Try different ethernet cables
• Renewed the DHCP lease System Preferences>Network select your ethernet connection then press "Advanced…" Select "TCP/IP" on the top tab press "Renew DHCP Lease" it might take a few seconds to get the IP address be patient.
Reset network setting (https://www.youtube.com/watch?v=Wg1gbXAe8pY&ab_channel=HOWZA)
• Added new location in Network System Preferences
• Disabled and re-enabled the Ethernet via terminal (with: sudo ifconfig en0 down & sudo ifconfig en0 up) https://macreports.com/mac-ethernet-not-working-how-to-fix/
• Reinstalled the Ethernet kernel extension. This is done with a terminal command. It deletes the old one and installs a new one at restart of the machine. (https://www.iphoneincanada.ca/mac/how-to-fix-mac-ethernet-port-not-working/)
• Created a new user (https://www.howtoisolve.com/dropping-ethernet-connection-on-mac-mac-mini-imac/)
• Turned off wake for network access. Apparently this worked for some people (https://discussions.apple.com/thread/252189073)
• Deleted the ethernet connection in System Preferences>Network select the ethernet or wifi that you want delete press the "-" press the "+" and select the one that you want to add depending of your hub you'll have different options.
• Configured the hardware manually under System Preferences>Network select your ethernet connection then press "Advanced…" the “hardware” tab on the top (https://www.caldigit.com/ethernet-port-on-the-ts4-or-ts3-plus-does-not-work-properly/)
Other things that you might look into:
Setting your IPv6 in to local System Preferences>Network select your ethernet connection then press "Advanced…" Select "TCP/IP" on the top tab under configure IPv6 select "Link-Local" Only
You might need to call your ISP to make sure that the are no problem with IPv6. Some people had to fully disable IPv6 on their machines or routers. If all of your other devices are working most likely this is not the issue. If this is the case you might want to look into NAT64 and make sure that your ISP has thing set up correctly for your service.
Hope this helps and saves people some hours.
