I’ve a 2015 MacBook Pro with no physical Ethernet port. Occasionally I need to connect directly to a system of several devices on a Brainboxes SW-504 Ethernet switch.

From an older MacBook with a built-in Ethernet port, this is a no-brainer — just plug into the switch and set my Ethernet IP address to an appropriate static IP and netmask.

From the newer MacBooks, I seem not to be able to make it work through a USB adapter. The network services panel keeps insisting that:

“Either the cable is unplugged or the other end is not responding.”

The adapter I’m using is an Insignia 3 USB Gigabit Ethernet Adapter (NS-PU98635).

I assume this is because the Insignia adapter’s driver is looking for a router and won't initialize until it finds one? Insignia support has confirmed that the model won’t work without a router connection. Does anyone know of one that will?

If there”s a way to make this work via some command line settings, great. I’ve put several hours into searching and found nothing. On the other hand, I’m more than willing to buy a different adapter that’s known to work in my situation.

  • The regular, non-USB 3.0—but still USB—adapter should work fine. Also, if you have a Thunderbolt port on that MacBook, the Apple Thunderbolt to Ethernet dongle should be fine. But that said, are you sure that the USB dongle doesn’t need a drive? To my knowledge any of those non-Apple USB adapters need drivers. Does it work with a router connection? Their site shows no explicit Apple support so that might be the issue. A dongle with a driver would not have this odd requirement. Jan 7, 2018 at 20:35
  • Correction: I saw that if you download the drivers directly there us a Mac specific.pkg installer in there. Did you install that? Without that driver, the adapter won’t work. Only Apple-made adapters (to the best of my knowledge) just work “plug and play” like that. Jan 7, 2018 at 22:26
  • @JakeGould Yes. I did install the driver package.
    – Mike Ellis
    Jan 8, 2018 at 14:02

1 Answer 1


I’ve used lots of different USB Ethernet adapters with Macs, always using macOS’s built-in USB Ethernet device class drivers, and I have never seen an adapter with the problem you’re describing. In fact it doesn’t make any sense that an Ethernet adapter could tell the difference between a switch and a router. I think literally any other adapter you could buy would not have the bug you’re experiencing.

  • Thanks, I'll order an Apple adaptor and see if that works. As to adapters not being able to tell the difference between a router and a switch, that's true from an electrical standpoint but not when it comes to software. It's quite possible to write a driver that waits for a dhcp response from a router and gives up if one is not received. Handling the case where the user wants a static ip requires extra work.
    – Mike Ellis
    Jan 8, 2018 at 14:07
  • @MikeEllis Well, the thing about this whole “router” connection explanation is it makes almost no sense at all. I almost want to get my hands on one of these adapters to see if what you are saying is true. It’s almost like you need to go out of your way to allow an adapter to behave like this and—if the behavior you are noticing—is really the case then why not more reports of this? Maybe this is a new product relatively speaking, but it just doesn’t make sense why an adapter in 2017 would be made like this. Jan 8, 2018 at 15:43
  • @JakeGould It astounds me, too, but I can totally imagine a manager tasked with keeping the cost down telling a developer not to waste time supporting static ip's because in 2017 no one uses those anymore. Plus we have the mfr's support team telling me it must have a router connection. My Apple adapter is arriving tomorrow. I'll post the outcome after I test it.
    – Mike Ellis
    Jan 8, 2018 at 18:54
  • @MikeEllis Be aware that Apple doesn't make a USB 3 / GigE adapter; Apple shipped Thunderbolt 1 before they shipped USB 3, so Apple made a Thunderbolt to GigE adapter, and they still sell a USB 2 to 10/100 Ethernet adapter that's many years old now. But I've used third-party USB 3 to GigE adapters from Belkin, Anker, and others, which all make use of macOS's built-in generic USB Ethernet device class drivers, and never had the problem you saw. It makes no sense to add any kind of IP knowledge at all to an Ethernet dongle, unless it provides Sleep Proxy or "Lights Out Management" features.
    – Spiff
    Jan 8, 2018 at 20:35
  • @Spiff The Thunderbolt is what ordered. I'll let you know how it works.
    – Mike Ellis
    Jan 9, 2018 at 3:28

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