Which company owns MAC address prefix D4:66:A8?

MAC address prefix D4:66:A8 is registered to Riedo Networks Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D4:66:A8 has a network interface built by Riedo Networks Ltd.

What is the OUI D4:66:A8?

D4:66:A8 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Riedo Networks Ltd. It covers every address from D4:66:A8:00:00:00 to D4:66:A8:FF:FF:FF, or 16,777,216 addresses in total. It is also written D4-66-A8.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in D4:66:A8:00:00:00 that is D4:66:A8 — 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 Riedo Networks Ltd located?

Riedo Networks Ltd is listed at Route de la Fonderie 6 Fribourg CH 1700 in the IEEE OUI registry entry for D4:66:A8. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Riedo Networks Ltd

MAC address prefix D4:66:A8 is registered to Riedo Networks Ltd in the IEEE OUI registry. Any device whose MAC address begins with D4:66:A8 has a network interface built by Riedo Networks Ltd. 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 D4:66:A8:00:00:00 to D4:66:A8:FF:FF:FF.

OUI prefix: D4:66:A8
Hyphen form: D4-66-A8
MAC range: D4:66:A8:00:00:00 – D4:66:A8:FF:FF:FF
Addresses in block: 16,777,216
Organization: Riedo Networks Ltd
Address: Route de la Fonderie 6 Fribourg CH 1700
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 (3)

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 "Riedo Networks GmbH"
archived source →
2018-12-21Renamed from "Riedo Networks GmbH" to "Riedo Networks Ltd"
archived source →
2026-07-17Assigned to "Riedo Networks Ltd"

Nearby in the registry

The prefixes assigned immediately before and after D4:66:A8:

FAQ

Which company owns MAC address prefix D4:66:A8?: MAC address prefix D4:66:A8 is registered to Riedo Networks Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D4:66:A8 has a network interface built by Riedo Networks Ltd.
What is the OUI D4:66:A8?: D4:66:A8 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Riedo Networks Ltd. It covers every address from D4:66:A8:00:00:00 to D4:66:A8:FF:FF:FF, or 16,777,216 addresses in total. It is also written D4-66-A8.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in D4:66:A8:00:00:00 that is D4:66:A8 — 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 Riedo Networks Ltd located?: Riedo Networks Ltd is listed at Route de la Fonderie 6 Fribourg CH 1700 in the IEEE OUI registry entry for D4:66:A8. This is the address the organization registered with the IEEE, which may differ from its current operating address.