Cannot connect MacBook Pro (Retina, 15-inch, Mid 2015) (10.13.3) to the internet through my Apple USB Ethernet Adapter. I am receiving this error under System Preferences/Network:

  • "Apple USB Ethernet Adapter has a self-assigned IP address and will not be able to connect to the Internet."
  • IP Address: 169.254.59.248
  • Subnet Mask: 255.255.0.0

I can connect to the internet with the same ethernet port on my Windows 10 machine. When I replace the IP address with a the Wi-Fi IP address I use to successfully connect to the same network under "Using DHCP with manual address", the Apple USB Ethernet Adapter icon is green and displays the message "Apple USB Ethernet Adapter is currently active and has the IP address xx.xx.xx.252." However there is no actual internet connection (i.e., I cannot visit any website).

According to this solution to a similar problem, I can:

  1. Find and disable whatever firewall is intercepting the DHCP return traffic. According to System Preferences/Security & Privacy/Firewall, my firewall is off. Is there anywhere else I can check for additional firewalls? Would firewalls somehow impact ethernet and Wi-fi differently?
  2. Inspect the network traffic or the router logs to see if and why the Mac DHCP broadcast packet is being ignored. How do I check network traffic on my Mac? I am comfortable using the terminal.

I have also tried steps listed as potential solutions in this post:

  1. To reset the firewall, go to the /Macintosh HD/Library/Preferences/ folder and remove the file called "com.apple.alf.plist," and then restart your computer. On my computer I went to /Library/Preferences/ and ran sudo rm com.apple.alf.plist
  2. If that was already set, try the "Advanced" button, then "Renew DHCP Lease"
  3. Removing their "Ethernet" config from the Network settings and then re-adding

Does anyone have other suggestions? Thanks in advance

  • This thread at Apple Communities may have some answers for you. – IconDaemon Mar 11 at 17:51
  • If it doesn't work with a manually assigned IP, DHCP is not the problem if you're on an ordinary home network. Try checking for example that your network cable is OK - i.e. try with another cable. – jksoegaard Mar 11 at 21:03

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