Optical Internetworking Forum

Any device whose MAC address begins with 00:0F:40 has a network interface built by Optical Internetworking Forum. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:0F:40

Organization

Optical Internetworking Forum

Address

48377 Fremont Blvd Fremont CA US 94538

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.