Semptian Technologies Ltd.

Any device whose MAC address begins with 00:21:45 has a network interface built by Semptian Technologies Ltd.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:21:45

Organization

Semptian Technologies Ltd.

Address

No. 809, Tower B, Shi Ji Ke Mao Beijing CN 100190

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.