Nortel Networks

Any device whose MAC address begins with A4:21:8A has a network interface built by Nortel 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

A4:21:8A

Organization

Nortel Networks

Address

CARRETERA BASE AEREA # 5850 Zapopan Jalisco MX 44130

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.