Which company owns MAC address prefix D0:21:F9?

MAC address prefix D0:21:F9 is registered to Ubiquiti Inc in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:21:F9 has a network interface built by Ubiquiti Inc.

What is the OUI D0:21:F9?

D0:21:F9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Ubiquiti Inc. It covers every address from D0:21:F9:00:00:00 to D0:21:F9:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-21-F9.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in D0:21:F9:00:00:00 that is D0:21:F9 — 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 Ubiquiti Inc located?

Ubiquiti Inc is listed at 685 Third Avenue, 27th Floor New York NY US New York NY 10017 in the IEEE OUI registry entry for D0:21:F9. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Ubiquiti Inc own?

Ubiquiti Inc holds 48 OUI prefixes in the IEEE registry, of which D0:21:F9 is one. A device made by Ubiquiti Inc could carry a MAC address from any of them.

Ubiquiti Inc

MAC address prefix D0:21:F9 is registered to Ubiquiti Inc in the IEEE OUI registry. Any device whose MAC address begins with D0:21:F9 has a network interface built by Ubiquiti Inc. 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 D0:21:F9:00:00:00 to D0:21:F9:FF:FF:FF.

OUI prefix: D0:21:F9
Hyphen form: D0-21-F9
MAC range: D0:21:F9:00:00:00 – D0:21:F9:FF:FF:FF
Addresses in block: 16,777,216
Organization: Ubiquiti Inc
Address: 685 Third Avenue, 27th Floor New York NY US New York NY 10017
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.

Other prefixes from Ubiquiti Inc

Ubiquiti Inc holds 48 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (3)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2020-08-05Assigned to "Ubiquiti Networks Inc."
archived source →
2023-07-11Renamed from "Ubiquiti Networks Inc." to "Ubiquiti Inc"
archived source →
2026-07-17Assigned to "Ubiquiti Inc"

Nearby in the registry

The prefixes assigned immediately before and after D0:21:F9:

FAQ

Which company owns MAC address prefix D0:21:F9?: MAC address prefix D0:21:F9 is registered to Ubiquiti Inc in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:21:F9 has a network interface built by Ubiquiti Inc.
What is the OUI D0:21:F9?: D0:21:F9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Ubiquiti Inc. It covers every address from D0:21:F9:00:00:00 to D0:21:F9:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-21-F9.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in D0:21:F9:00:00:00 that is D0:21:F9 — 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 Ubiquiti Inc located?: Ubiquiti Inc is listed at 685 Third Avenue, 27th Floor New York NY US New York NY 10017 in the IEEE OUI registry entry for D0:21:F9. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Ubiquiti Inc own?: Ubiquiti Inc holds 48 OUI prefixes in the IEEE registry, of which D0:21:F9 is one. A device made by Ubiquiti Inc could carry a MAC address from any of them.