Which company owns MAC address prefix 84:5B:0C?

MAC address prefix 84:5B:0C is registered to eFAB P.S.A. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 84:5B:0C has a network interface built by eFAB P.S.A..

What is the OUI 84:5B:0C?

84:5B:0C is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to eFAB P.S.A.. It covers every address from 84:5B:0C:00:00:00 to 84:5B:0C:FF:FF:FF, or 16,777,216 addresses in total. It is also written 84-5B-0C.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 84:5B:0C:00:00:00 that is 84:5B:0C — 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 eFAB P.S.A. located?

eFAB P.S.A. is listed at al. Solidarości 129/131/197 VATID: PL5272968735 Warsaw Mazowieckie PL 00-898 in the IEEE OUI registry entry for 84:5B:0C. This is the address the organization registered with the IEEE, which may differ from its current operating address.

eFAB P.S.A.

MAC address prefix 84:5B:0C is registered to eFAB P.S.A. in the IEEE OUI registry. Any device whose MAC address begins with 84:5B:0C has a network interface built by eFAB P.S.A.. 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 84:5B:0C:00:00:00 to 84:5B:0C:FF:FF:FF.

OUI prefix: 84:5B:0C
Hyphen form: 84-5B-0C
MAC range: 84:5B:0C:00:00:00 – 84:5B:0C:FF:FF:FF
Addresses in block: 16,777,216
Organization: eFAB P.S.A.
Address: al. Solidarości 129/131/197 VATID: PL5272968735 Warsaw Mazowieckie PL 00-898
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.

2026-01-08Assigned to "eFAB P.S.A."
archived source →
2026-07-17Assigned to "eFAB P.S.A."

Nearby in the registry

The prefixes assigned immediately before and after 84:5B:0C:

FAQ

Which company owns MAC address prefix 84:5B:0C?: MAC address prefix 84:5B:0C is registered to eFAB P.S.A. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 84:5B:0C has a network interface built by eFAB P.S.A..
What is the OUI 84:5B:0C?: 84:5B:0C is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to eFAB P.S.A.. It covers every address from 84:5B:0C:00:00:00 to 84:5B:0C:FF:FF:FF, or 16,777,216 addresses in total. It is also written 84-5B-0C.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 84:5B:0C:00:00:00 that is 84:5B:0C — 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 eFAB P.S.A. located?: eFAB P.S.A. is listed at al. Solidarości 129/131/197 VATID: PL5272968735 Warsaw Mazowieckie PL 00-898 in the IEEE OUI registry entry for 84:5B:0C. This is the address the organization registered with the IEEE, which may differ from its current operating address.