If you have carefully set the first octet and the change still fails, consider these edge cases:
Many network interface cards (NICs) or network drivers will reject a spoofed MAC address if it is invalid or violates specific networking rules.
The MAC address is typically written in the format XX:XX:XX:XX:XX:XX , where each X is a hexadecimal digit. Some network administrators or users might need to change their device's MAC address for various reasons, such as network configuration requirements or troubleshooting. If you have carefully set the first octet
If the change doesn't take effect immediately, try the Wi-Fi adapter in your Network Connections settings. Summary of Constraints
When you see "Set the first octet work" , the software is telling you: Choose a first octet that has bit 2 = 1. If the change doesn't take effect immediately, try
To fix this error, you almost certainly need to adjust the of your desired MAC address.
, signaling to the driver that this is a intentional, locally assigned address. Information Security Stack Exchange Technical Barriers to Changing MAC Addresses , signaling to the driver that this is
The of the first octet determines if a frame is meant for a single device (unicast) or multiple devices (multicast/broadcast). For a standard network interface to function, this bit must always be 0 .
: The second-least significant bit of the first octet determines if the address is a Globally Unique (OUI-enforced) or Locally Administered address.
: Microsoft and hardware vendors have updated Wi-Fi drivers to block arbitrary MAC spoofing to prevent network conflicts.
: Ensure the second character is 2, 6, A, or E . (Example: 021122334455 ).