Which company owns MAC address prefix 84:5A:81?

MAC address prefix 84:5A:81 is registered to ffly4u in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 84:5A:81 has a network interface built by ffly4u.

What is the OUI 84:5A:81?

84:5A:81 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ffly4u. It covers every address from 84:5A:81:00:00:00 to 84:5A:81:FF:FF:FF, or 16,777,216 addresses in total. It is also written 84-5A-81.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 84:5A:81:00:00:00 that is 84:5A:81 — 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 ffly4u located?

ffly4u is listed at 3, avenue Didier Daurat Toulouse FR 31400 in the IEEE OUI registry entry for 84:5A:81. This is the address the organization registered with the IEEE, which may differ from its current operating address.

ffly4u

MAC address prefix 84:5A:81 is registered to ffly4u in the IEEE OUI registry. Any device whose MAC address begins with 84:5A:81 has a network interface built by ffly4u. 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 84:5A:81:00:00:00 to 84:5A:81:FF:FF:FF.

OUI prefix: 84:5A:81
Hyphen form: 84-5A-81
MAC range: 84:5A:81:00:00:00 – 84:5A:81:FF:FF:FF
Addresses in block: 16,777,216
Organization: ffly4u
Address: 3, avenue Didier Daurat Toulouse FR 31400
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.

2017-09-08Assigned to "ffly4u"
archived source →
2026-07-17Assigned to "ffly4u"

Nearby in the registry

The prefixes assigned immediately before and after 84:5A:81:

FAQ

Which company owns MAC address prefix 84:5A:81?: MAC address prefix 84:5A:81 is registered to ffly4u in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 84:5A:81 has a network interface built by ffly4u.
What is the OUI 84:5A:81?: 84:5A:81 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ffly4u. It covers every address from 84:5A:81:00:00:00 to 84:5A:81:FF:FF:FF, or 16,777,216 addresses in total. It is also written 84-5A-81.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 84:5A:81:00:00:00 that is 84:5A:81 — 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 ffly4u located?: ffly4u is listed at 3, avenue Didier Daurat Toulouse FR 31400 in the IEEE OUI registry entry for 84:5A:81. This is the address the organization registered with the IEEE, which may differ from its current operating address.