Which company owns MAC address prefix D0:CF:5E?

MAC address prefix D0:CF:5E is registered to Energy Micro AS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:CF:5E has a network interface built by Energy Micro AS.

What is the OUI D0:CF:5E?

D0:CF:5E is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Energy Micro AS. It covers every address from D0:CF:5E:00:00:00 to D0:CF:5E:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-CF-5E.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in D0:CF:5E:00:00:00 that is D0:CF:5E — 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 Energy Micro AS located?

Energy Micro AS is listed at Sandakerveien 118 Oslo NO N-0484 in the IEEE OUI registry entry for D0:CF:5E. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Energy Micro AS

MAC address prefix D0:CF:5E is registered to Energy Micro AS in the IEEE OUI registry. Any device whose MAC address begins with D0:CF:5E has a network interface built by Energy Micro AS. 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 D0:CF:5E:00:00:00 to D0:CF:5E:FF:FF:FF.

OUI prefix: D0:CF:5E
Hyphen form: D0-CF-5E
MAC range: D0:CF:5E:00:00:00 – D0:CF:5E:FF:FF:FF
Addresses in block: 16,777,216
Organization: Energy Micro AS
Address: Sandakerveien 118 Oslo NO N-0484
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 "Energy Micro AS"
archived source →
2026-07-17Assigned to "Energy Micro AS"

Nearby in the registry

The prefixes assigned immediately before and after D0:CF:5E:

FAQ

Which company owns MAC address prefix D0:CF:5E?: MAC address prefix D0:CF:5E is registered to Energy Micro AS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:CF:5E has a network interface built by Energy Micro AS.
What is the OUI D0:CF:5E?: D0:CF:5E is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Energy Micro AS. It covers every address from D0:CF:5E:00:00:00 to D0:CF:5E:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-CF-5E.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in D0:CF:5E:00:00:00 that is D0:CF:5E — 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 Energy Micro AS located?: Energy Micro AS is listed at Sandakerveien 118 Oslo NO N-0484 in the IEEE OUI registry entry for D0:CF:5E. This is the address the organization registered with the IEEE, which may differ from its current operating address.