Which company owns MAC address prefix A0:21:B7?

MAC address prefix A0:21:B7 is registered to NETGEAR in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:21:B7 has a network interface built by NETGEAR.

What is the OUI A0:21:B7?

A0:21:B7 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to NETGEAR. It covers every address from A0:21:B7:00:00:00 to A0:21:B7:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-21-B7.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A0:21:B7:00:00:00 that is A0:21:B7 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is NETGEAR located?

NETGEAR is listed at 3553 N. First Street San Jose CA US 95134 in the IEEE OUI registry entry for A0:21:B7. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does NETGEAR own?

NETGEAR holds 76 OUI prefixes in the IEEE registry, of which A0:21:B7 is one. A device made by NETGEAR could carry a MAC address from any of them.

NETGEAR

MAC address prefix A0:21:B7 is registered to NETGEAR in the IEEE OUI registry. Any device whose MAC address begins with A0:21:B7 has a network interface built by NETGEAR. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from A0:21:B7:00:00:00 to A0:21:B7:FF:FF:FF.

OUI prefix: A0:21:B7
Hyphen form: A0-21-B7
MAC range: A0:21:B7:00:00:00 – A0:21:B7:FF:FF:FF
Addresses in block: 16,777,216
Organization: NETGEAR
Address: 3553 N. First Street San Jose CA US 95134
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.

Other prefixes from NETGEAR

NETGEAR holds 76 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2016-07-29Assigned to "NETGEAR"
archived source →
2026-07-17Assigned to "NETGEAR"

Nearby in the registry

The prefixes assigned immediately before and after A0:21:B7:

FAQ

Which company owns MAC address prefix A0:21:B7?: MAC address prefix A0:21:B7 is registered to NETGEAR in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:21:B7 has a network interface built by NETGEAR.
What is the OUI A0:21:B7?: A0:21:B7 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to NETGEAR. It covers every address from A0:21:B7:00:00:00 to A0:21:B7:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-21-B7.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A0:21:B7:00:00:00 that is A0:21:B7 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is NETGEAR located?: NETGEAR is listed at 3553 N. First Street San Jose CA US 95134 in the IEEE OUI registry entry for A0:21:B7. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does NETGEAR own?: NETGEAR holds 76 OUI prefixes in the IEEE registry, of which A0:21:B7 is one. A device made by NETGEAR could carry a MAC address from any of them.