Which company owns MAC address prefix 04:81:AE?

MAC address prefix 04:81:AE is registered to Clack Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 04:81:AE has a network interface built by Clack Corporation.

What is the OUI 04:81:AE?

04:81:AE is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Clack Corporation. It covers every address from 04:81:AE:00:00:00 to 04:81:AE:FF:FF:FF, or 16,777,216 addresses in total. It is also written 04-81-AE.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 04:81:AE:00:00:00 that is 04:81:AE — 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 Clack Corporation located?

Clack Corporation is listed at 4462 Duraform Lane Windsor WI US 53598 in the IEEE OUI registry entry for 04:81:AE. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Clack Corporation

MAC address prefix 04:81:AE is registered to Clack Corporation in the IEEE OUI registry. Any device whose MAC address begins with 04:81:AE has a network interface built by Clack Corporation. 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 04:81:AE:00:00:00 to 04:81:AE:FF:FF:FF.

OUI prefix: 04:81:AE
Hyphen form: 04-81-AE
MAC range: 04:81:AE:00:00:00 – 04:81:AE:FF:FF:FF
Addresses in block: 16,777,216
Organization: Clack Corporation
Address: 4462 Duraform Lane Windsor WI US 53598
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.

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 "Clack Corporation"
archived source →
2026-07-17Assigned to "Clack Corporation"

Nearby in the registry

The prefixes assigned immediately before and after 04:81:AE:

FAQ

Which company owns MAC address prefix 04:81:AE?: MAC address prefix 04:81:AE is registered to Clack Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 04:81:AE has a network interface built by Clack Corporation.
What is the OUI 04:81:AE?: 04:81:AE is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Clack Corporation. It covers every address from 04:81:AE:00:00:00 to 04:81:AE:FF:FF:FF, or 16,777,216 addresses in total. It is also written 04-81-AE.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 04:81:AE:00:00:00 that is 04:81:AE — 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 Clack Corporation located?: Clack Corporation is listed at 4462 Duraform Lane Windsor WI US 53598 in the IEEE OUI registry entry for 04:81:AE. This is the address the organization registered with the IEEE, which may differ from its current operating address.