I heard that each vendor is given a specific start in the Mac Address to use.

What's the problem of me creating a company and using the start of Mac Address given to google or Cisco? how is this enforced at all?

  • If you do that, expect huge legal costs to defend yourself.
    – Ron Maupin
    Jul 17 at 13:37

The original owner of the OUI or IEEE might take legal actions against you.


If two devices use the same MAC address they won't function correctly on a LAN. Similar issues could happen with Bluetooth and other technologies which depend on the uniqueness guarantee of MAC addresses.

IEEE previously allocated OUI addresses in a sequential manner. Some manufacturers simply stopped paying for allocations, and began squatting on blocks they knew were unused and, under the old allocation method, wouldn't be anytime soon. IEEE saw this as problematic (for everyone, not just their revenue) and started allocating OUI addresses randomly to discourage squatting.

  • 1
    And some vendors were caught recycling their OUI(s). (the 24-bit counter rolls over and manufacturing kept going.)
    – Ricky
    Jul 17 at 22:45

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