Which company owns MAC address prefix 20:91:D9?

MAC address prefix 20:91:D9 is registered to I'M SPA in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 20:91:D9 has a network interface built by I'M SPA.

What is the OUI 20:91:D9?

20:91:D9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to I'M SPA. It covers every address from 20:91:D9:00:00:00 to 20:91:D9:FF:FF:FF, or 16,777,216 addresses in total. It is also written 20-91-D9.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 20:91:D9:00:00:00 that is 20:91:D9 — 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 I'M SPA located?

I'M SPA is listed at VIA BIRON 102/3 MONTEVIALE VICENZA IT 36050 in the IEEE OUI registry entry for 20:91:D9. This is the address the organization registered with the IEEE, which may differ from its current operating address.

I'M SPA

MAC address prefix 20:91:D9 is registered to I'M SPA in the IEEE OUI registry. Any device whose MAC address begins with 20:91:D9 has a network interface built by I'M SPA. 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 20:91:D9:00:00:00 to 20:91:D9:FF:FF:FF.

OUI prefix: 20:91:D9
Hyphen form: 20-91-D9
MAC range: 20:91:D9:00:00:00 – 20:91:D9:FF:FF:FF
Addresses in block: 16,777,216
Organization: I'M SPA
Address: VIA BIRON 102/3 MONTEVIALE VICENZA IT 36050
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 "I'M SPA"
archived source →
2026-07-17Assigned to "I'M SPA"

Nearby in the registry

The prefixes assigned immediately before and after 20:91:D9:

FAQ

Which company owns MAC address prefix 20:91:D9?: MAC address prefix 20:91:D9 is registered to I'M SPA in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 20:91:D9 has a network interface built by I'M SPA.
What is the OUI 20:91:D9?: 20:91:D9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to I'M SPA. It covers every address from 20:91:D9:00:00:00 to 20:91:D9:FF:FF:FF, or 16,777,216 addresses in total. It is also written 20-91-D9.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 20:91:D9:00:00:00 that is 20:91:D9 — 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 I'M SPA located?: I'M SPA is listed at VIA BIRON 102/3 MONTEVIALE VICENZA IT 36050 in the IEEE OUI registry entry for 20:91:D9. This is the address the organization registered with the IEEE, which may differ from its current operating address.