Bay Networks

Any device whose MAC address begins with 00:00:81 has a network interface built by Bay Networks. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:00:81

Organization

Bay Networks

Address

PO Box 58185 Santa Clara CA US 95052-8185

Source

IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.