Which company owns MAC address prefix 88:91:DD?

MAC address prefix 88:91:DD is registered to Racktivity in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 88:91:DD has a network interface built by Racktivity.

What is the OUI 88:91:DD?

88:91:DD is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Racktivity. It covers every address from 88:91:DD:00:00:00 to 88:91:DD:FF:FF:FF, or 16,777,216 addresses in total. It is also written 88-91-DD.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 88:91:DD:00:00:00 that is 88:91:DD — 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 Racktivity located?

Racktivity is listed at Hertstokweg 5 Ternat Flanders BE 1741 in the IEEE OUI registry entry for 88:91:DD. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Racktivity

MAC address prefix 88:91:DD is registered to Racktivity in the IEEE OUI registry. Any device whose MAC address begins with 88:91:DD has a network interface built by Racktivity. 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 88:91:DD:00:00:00 to 88:91:DD:FF:FF:FF.

OUI prefix: 88:91:DD
Hyphen form: 88-91-DD
MAC range: 88:91:DD:00:00:00 – 88:91:DD:FF:FF:FF
Addresses in block: 16,777,216
Organization: Racktivity
Address: Hertstokweg 5 Ternat Flanders BE 1741
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 "Racktivity"
archived source →
2026-07-17Assigned to "Racktivity"

Nearby in the registry

The prefixes assigned immediately before and after 88:91:DD:

FAQ

Which company owns MAC address prefix 88:91:DD?: MAC address prefix 88:91:DD is registered to Racktivity in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 88:91:DD has a network interface built by Racktivity.
What is the OUI 88:91:DD?: 88:91:DD is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Racktivity. It covers every address from 88:91:DD:00:00:00 to 88:91:DD:FF:FF:FF, or 16,777,216 addresses in total. It is also written 88-91-DD.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 88:91:DD:00:00:00 that is 88:91:DD — 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 Racktivity located?: Racktivity is listed at Hertstokweg 5 Ternat Flanders BE 1741 in the IEEE OUI registry entry for 88:91:DD. This is the address the organization registered with the IEEE, which may differ from its current operating address.