USB-Ethernet adapter changes MAC address everytime

Discussion in 'Mac OS X Server, Xserve, and Networking' started by jaihindhreddy, Jun 6, 2016.

  1. jaihindhreddy macrumors newbie

    Feb 14, 2013
    I got a generic USB to Ethernet adapter. Wasn't detected. Did what's mentioned here:
    Its now being detected but shows different a MAC address each time in Network Utility.
    I have to submit my MAC address at the workplace for them to unblock.
    I'm trying to spoof it in terminal with
    sudo ifconfig en4 ether 00:09:ef:a8:c9:7e
    That doesn't work either.
    Plugged it into a Windows 10 computer (without installing any drivers) and it wasn't detected.
    Hope you guys can help here.
  2. wirefire macrumors member

    Jun 12, 2015
    If the USB device does not have a specific MAC address on the outside of the device and it is a "cheap" adapter. It is likely that the mac address is a software programmable MAC address that is assigned by the driver at load. I think these are the worst invention ever created but just like there are software based modems and com ports there are software based network cards.

    your spoofing command looks correct (provided that your interface is en4) but there is no guarantee that what you are using for an interface or MAC address is valid. The interface name can be found with ifconfig. It should be en0 unless you have a lot of ethernet interfaces. It is possible that since you are using a non-apple approved driver, it may create the interface with a different name as a reference. Also there are certain requirements for what mac addresses are allowed and what ones are not allowed.

    Since apple sells their own model for $29. I really do not see the merit in the time and effort involved in trying to do this with a generic adapter. Plus those instructions disable driver signing and malware protection in the mac which is generally under the realm of "bad idea" unless you are making a hackintosh. If you should decide to use the apple one, you should remove that ktext you downloaded and installed and run "csrutil enable" to enable the protection mode. and take the mac out of developer mode.
  3. jaihindhreddy thread starter macrumors newbie

    Feb 14, 2013
    Thank you for that. And yes, that thing was cheap. The problem is, I am not in a city and here in India, shipping from online stores takes some time(~1 week). That was the only thing available here. It works for other networks but here they need one MAC address to unblock. I Installed spoofMac after some googling and even it shows 'en4' for the adapter. I guess I have to get one that actually works. Will this do?®-Alu...5397369&sr=8-9&keywords=satechi+USB+aluminium
    Or should I just get an apple one?
  4. Ulugbek Ro'zimboyev macrumors newbie

    Nov 10, 2016
    Did you solve this problem, I have also this problem. Please, give me any direction
  5. adamp916 macrumors newbie


    Mar 17, 2017
    Although these particular USB NICs are cheap, the ability to spoof a MAC address has absolutely nothing to do with being cheap. Every NIC is supposed to have a unique MAC Address, but nearly every driver (or LAN device) has the ability to do spoofing these days. Nothing will change the hardware MAC Address, but you can make every device connected to it THINK it's different. In fact, I would argue that you're more likely to find drivers that don't allow spoofing on a cheap NIC.

    Regardless, I stumbled upon this post because I have the same USB devices with identical MACs. $2 off ebay from China. When they manufactured these things they made them identical (like I-D-E-N-T-I-C-A-L)
  6. belvdr macrumors 603

    Aug 15, 2005
    No longer logging into MR
    I remember the Sun QFE adapters would give the same MAC address to all ports on the adapter. This was fine if each port went to a different VLAN, such as firewalls, but caused all sorts of pain otherwise. I wonder if these cheap USB adapters dynamically assign a MAC address when the driver loads. I know Hyper-V will dynamically assign a MAC address when a VM is power-cycled, unless you specifically configure the VM to have a static MAC.

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5 June 6, 2016