Thunderbolt Ethernet Self-Assigned IP

owen.meredith

macrumors member
Original poster
Sep 9, 2015
36
105
Hey guys!


So earlier today I bought a USB ethernet adapter, as last night the shared Wifi in my apartment complex was going extremely slow (and i noticed there was an ethernet cable coming through the wall). I didn't realise the adapter I bought was a 10/100, which was fine as the internet capped at 100MB but seeing as the connection is 1GB it made sense to buy a better adapter from the Apple Store a 10 minute walk away. So I bought a gigabit thunderbolt ethernet adapter, came home, unplugged the other one and got the "self-assigned IP" issue. After deleting the usual plist files, smc reset etc. I plugged the USB one back in and it's also giving me the same error too. The Wifi connects with no issue, it's just strange the USB adapter worked straight away and now it doesn't! I've trawled through many recommendations but i'm stumped on this one! Maybe it's a router issue, but I don't have access to the router here officially (I could go out into the hallway and open the panel that it's in and reset it, but there's another 5 residents here). It's just strange that it worked with the USB adapter first and now with neither one of them!


Any help would be appreciated!
 

chabig

macrumors 603
Sep 6, 2002
5,877
3,139
I wouldn't go deleting files trying to make it work. Try rebooting the Mac. That'll force your network interfaces to be set up again from scratch.
 

owen.meredith

macrumors member
Original poster
Sep 9, 2015
36
105
I wouldn't go deleting files trying to make it work. Try rebooting the Mac. That'll force your network interfaces to be set up again from scratch.
It's only plist files that get recreated - essentially resetting any settings. I've tried resetting lots, along with pram/vram resets but still nothing! I'm going to boot camp with Windows 10 and see if it works there - if so then it's a OS issue, and if not then it's a router issue.
 

chabig

macrumors 603
Sep 6, 2002
5,877
3,139
You could try deleting and recreating the USB ethernet interface in System Preferences. Is wifi turned off so ethernet is the only active interface? Can you reboot the router?
 

owen.meredith

macrumors member
Original poster
Sep 9, 2015
36
105
You could try deleting and recreating the USB ethernet interface in System Preferences. Is wifi turned off so ethernet is the only active interface? Can you reboot the router?
I've tried doing this for both the USB and Thunderbolt adapters. I've also tried changing Locations in the network tab to no avail - it's just strange that it worked like a charm first time, but after that it's failed (which the USB adapter that first worked).

Resetting the router is honestly my last resort, as it's something I can't do easily (see above). However, if nothing else works then I guess i'll have to do it in the middle of the night when all my neighbours are asleep! I'm sure that would fix the problem, but it's just difficult to do. I'll see if it work with Windows 10, as if the problem remains that it's something to do with the router and i'll have no choice but to reset it. However, if it does indeed work with W10 then it's a MacOS issue.