Which company owns MAC address prefix 40:DC:9D?

MAC address prefix 40:DC:9D is registered to HAJEN in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 40:DC:9D has a network interface built by HAJEN.

What is the OUI 40:DC:9D?

40:DC:9D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to HAJEN. It covers every address from 40:DC:9D:00:00:00 to 40:DC:9D:FF:FF:FF, or 16,777,216 addresses in total. It is also written 40-DC-9D.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 40:DC:9D:00:00:00 that is 40:DC:9D — 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 HAJEN located?

HAJEN is listed at 102-1302, Sinwon-ro 88, Yeongtong-gu Suwon-Si Gyeonggi-do KR 16681 in the IEEE OUI registry entry for 40:DC:9D. This is the address the organization registered with the IEEE, which may differ from its current operating address.

HAJEN

MAC address prefix 40:DC:9D is registered to HAJEN in the IEEE OUI registry. Any device whose MAC address begins with 40:DC:9D has a network interface built by HAJEN. 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 40:DC:9D:00:00:00 to 40:DC:9D:FF:FF:FF.

OUI prefix: 40:DC:9D
Hyphen form: 40-DC-9D
MAC range: 40:DC:9D:00:00:00 – 40:DC:9D:FF:FF:FF
Addresses in block: 16,777,216
Organization: HAJEN
Address: 102-1302, Sinwon-ro 88, Yeongtong-gu Suwon-Si Gyeonggi-do KR 16681
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.

2018-12-21Assigned to "HAJEN"
archived source →
2026-07-17Assigned to "HAJEN"

Nearby in the registry

The prefixes assigned immediately before and after 40:DC:9D:

FAQ

Which company owns MAC address prefix 40:DC:9D?: MAC address prefix 40:DC:9D is registered to HAJEN in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 40:DC:9D has a network interface built by HAJEN.
What is the OUI 40:DC:9D?: 40:DC:9D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to HAJEN. It covers every address from 40:DC:9D:00:00:00 to 40:DC:9D:FF:FF:FF, or 16,777,216 addresses in total. It is also written 40-DC-9D.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 40:DC:9D:00:00:00 that is 40:DC:9D — 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 HAJEN located?: HAJEN is listed at 102-1302, Sinwon-ro 88, Yeongtong-gu Suwon-Si Gyeonggi-do KR 16681 in the IEEE OUI registry entry for 40:DC:9D. This is the address the organization registered with the IEEE, which may differ from its current operating address.