I recently got a Macbook pro 13 inch and I bought this docking station for all the ports I need. The issue is that my university network requires registration of mac id to use internet in campus and it's a cumbersome process. I already have a windows laptop that is registered so I wanted to change the mac id to start using my macbook. I followed this article to change my mac id, but I noticed two interfaces en1 and bridge0 have the same mac id, and I can only change mac id for bridge0 interface. Although changing mac id of bridge0 interface changes the mac id displayed in the advanced properties of Thunderbolt Bridge service in Network Preferences I still can't access internet. I am quite new to Mac OS and changing these stuff were quite simple in Windows, is there any way I can achieve what I want??

Update 1

I had a portable Windows installation lying around and I used it to boot into Windows on my macbook and I can change mac id and access internet perfectly on Windows, so it can't be related to any faulty hardware.

Update 2

After again booting into mac os now the interface in properly recognized in Network Preference as USB 10/100/1000 LAN and new interface name en7. I guess I only had to reboot after intallation of drivers but mac os didn't prompt me to do so. I followed the same article I linked before and trying to change mac id results in an error with message:

ifconfig: ioctl (SIOCAIFADDR): Operation not supported on socket

Also, using spoofmac as suggested results in same error as spoof-mac uses the same method to change mac id.

  • And if you go to System Preferences > Network > (Select the interface you want to change) > Advanced > Hardware. It is either not there or not changeable? Oct 28 '20 at 16:28
  • I don't get it, the way the linked article described you can only view the mac id in the hardware section, to change mac id I had to use terminal. And as I said I couldn't change mac id for en1 interface while I could change mac id for bridge0 interface. And when I changed bridge0 interface mac id I saw the change reflected in the hardware section. Oct 28 '20 at 16:57
  • MAC are burned into the hardware of the NIC. What you're doing by "changing" it is causing the software to lie about what the MAC address is. macOS used to permit this. It no longer does. Oct 28 '20 at 18:24
  • @MarcWilson changing mac id is still supported for some interfaces but not all. Oct 29 '20 at 5:34
  • That's weird...I got mine to work on Catalina with a Thunderbolt to Ethernet adapter. It might be the USB device that for some reason isn't allowing it.
    – Allan
    Oct 29 '20 at 14:58

macOS has always been "iffy" when it came to spoofing MAC addresses unlike other OSes so it's not a (faulty) hardware issue. It's more of a "how Apple likes to do things" issue.

My advice is the following (in order):

  • Get that MAC address registered with the university.
  • Use SpoofMAC to, well, spoof your MAC address.

Yes, I think you should just bite the bullet and register your MAC with the university. Yes, it's a PITA, but the downside is simply too costly for the time you're attempting to save. If they happen to catch you (and they can), you're going to face disciplinary action because in the end, you agreed to their terms of service whether you remember agreeing to them or not.

That said, there are genuine uses for spoofing your MAC address and to do so on a Mac, you can use SpoofMAC. It's available via GitHub (see link above) or via Homebrew.

Once you have it installed, you simiply execute the following command with the actual MAC address and your network device as needed:

% spoof-mac.py set 00:00:00:00:00:00 en0

They also conveniently provide instructions for launching this at startup.

  • My university allows only one mac id per student for ethernet connection (no restriction on wifi), as long as I am using the same id registered by me on my device I am not violating any TOS. Also, I tried spoofMac and it failed (more details added to post), guess I have to do it the hard way, the reason I don't want to register my device again is cause it will take at least a week to take effect and my device will be unusable in that time. Oct 29 '20 at 5:40
  • Just out of curiosity, can you register a small router like a Linksys or a Netgear? You don't need anything fancy, even a used cheap one will do. In fact, you can spoof the MAC to your registered one and the router will show only that MAC for for the devices behind it. This router here with DDWRT does this. It can't be a switch, it has to be a router with NAT, but with the built in switch, you can have multiple Ethernet connections. Just don't turn on WiFi as it will be seen by any/everyone in the vicinity.
    – Allan
    Oct 29 '20 at 15:02

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