Which company owns MAC address prefix 00:90:CD?

MAC address prefix 00:90:CD is registered to ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 00:90:CD has a network interface built by ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A..

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 00:90:CD:00:00:00 that is 00:90:CD — 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 ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. located?

ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. is listed at R. ENG FREDERICO ULRICH - APARTADO 3081 Guardeiras - 4470 Moreira Maia PT in the IEEE OUI registry entry for 00:90:CD. This is the address the organization registered with the IEEE, which may differ from its current operating address.

ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A.

MAC address prefix 00:90:CD is registered to ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. in the IEEE OUI registry. Any device whose MAC address begins with 00:90:CD has a network interface built by ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A.. 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 00:90:CD:00:00:00 to 00:90:CD:FF:FF:FF.

OUI prefix: 00:90:CD
Hyphen form: 00-90-CD
MAC range: 00:90:CD:00:00:00 – 00:90:CD:FF:FF:FF
Addresses in block: 16,777,216
Organization: ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A.
Address: R. ENG FREDERICO ULRICH - APARTADO 3081 Guardeiras - 4470 Moreira Maia PT
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 "ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A."
archived source →
2026-07-17Assigned to "ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A."

Nearby in the registry

The prefixes assigned immediately before and after 00:90:CD:

FAQ

Which company owns MAC address prefix 00:90:CD?: MAC address prefix 00:90:CD is registered to ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 00:90:CD has a network interface built by ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A..
What is the OUI 00:90:CD?: 00:90:CD is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A.. It covers every address from 00:90:CD:00:00:00 to 00:90:CD:FF:FF:FF, or 16,777,216 addresses in total. It is also written 00-90-CD.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 00:90:CD:00:00:00 that is 00:90:CD — 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 ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. located?: ENT-EMPRESA NACIONAL DE TELECOMMUNICACOES, S.A. is listed at R. ENG FREDERICO ULRICH - APARTADO 3081 Guardeiras - 4470 Moreira Maia PT in the IEEE OUI registry entry for 00:90:CD. This is the address the organization registered with the IEEE, which may differ from its current operating address.