J125, NATIONAL SECURITY AGENCY

Any device whose MAC address begins with 00:20:91 has a network interface built by J125, NATIONAL SECURITY AGENCY. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:20:91

Organization

J125, NATIONAL SECURITY AGENCY

Address

9800 SAVAGE ROAD FT. MEADE MD US 20755-6000

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.