Which company owns MAC address prefix A0:5B:21?

MAC address prefix A0:5B:21 is registered to ENVINET GmbH in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:5B:21 has a network interface built by ENVINET GmbH.

What is the OUI A0:5B:21?

A0:5B:21 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ENVINET GmbH. It covers every address from A0:5B:21:00:00:00 to A0:5B:21:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-5B-21.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A0:5B:21:00:00:00 that is A0:5B:21 — 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 ENVINET GmbH located?

ENVINET GmbH is listed at Hans-Pinsel-Str. 4 Haar DE 85540 in the IEEE OUI registry entry for A0:5B:21. This is the address the organization registered with the IEEE, which may differ from its current operating address.

ENVINET GmbH

MAC address prefix A0:5B:21 is registered to ENVINET GmbH in the IEEE OUI registry. Any device whose MAC address begins with A0:5B:21 has a network interface built by ENVINET GmbH. 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 A0:5B:21:00:00:00 to A0:5B:21:FF:FF:FF.

OUI prefix: A0:5B:21
Hyphen form: A0-5B-21
MAC range: A0:5B:21:00:00:00 – A0:5B:21:FF:FF:FF
Addresses in block: 16,777,216
Organization: ENVINET GmbH
Address: Hans-Pinsel-Str. 4 Haar DE 85540
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 "ENVINET GmbH"
archived source →
2026-07-17Assigned to "ENVINET GmbH"

Nearby in the registry

The prefixes assigned immediately before and after A0:5B:21:

FAQ

Which company owns MAC address prefix A0:5B:21?: MAC address prefix A0:5B:21 is registered to ENVINET GmbH in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:5B:21 has a network interface built by ENVINET GmbH.
What is the OUI A0:5B:21?: A0:5B:21 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ENVINET GmbH. It covers every address from A0:5B:21:00:00:00 to A0:5B:21:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-5B-21.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A0:5B:21:00:00:00 that is A0:5B:21 — 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 ENVINET GmbH located?: ENVINET GmbH is listed at Hans-Pinsel-Str. 4 Haar DE 85540 in the IEEE OUI registry entry for A0:5B:21. This is the address the organization registered with the IEEE, which may differ from its current operating address.