CoreOS

Any device whose MAC address begins with B4:74:47 has a network interface built by CoreOS. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

B4:74:47

Organization

CoreOS

Address

PO Box 7775 #55097 San Francisco CA US 94120-7775

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.