Which company owns MAC address prefix B4:EF:04?

MAC address prefix B4:EF:04 is registered to DAIHAN Scientific Co., Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with B4:EF:04 has a network interface built by DAIHAN Scientific Co., Ltd..

What is the OUI B4:EF:04?

B4:EF:04 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to DAIHAN Scientific Co., Ltd.. It covers every address from B4:EF:04:00:00:00 to B4:EF:04:FF:FF:FF, or 16,777,216 addresses in total. It is also written B4-EF-04.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in B4:EF:04:00:00:00 that is B4:EF:04 — 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 DAIHAN Scientific Co., Ltd. located?

DAIHAN Scientific Co., Ltd. is listed at 326, Sinpyoungsukhwaro Wonju-si, Gangwon-do KR 26358 in the IEEE OUI registry entry for B4:EF:04. This is the address the organization registered with the IEEE, which may differ from its current operating address.

DAIHAN Scientific Co., Ltd.

MAC address prefix B4:EF:04 is registered to DAIHAN Scientific Co., Ltd. in the IEEE OUI registry. Any device whose MAC address begins with B4:EF:04 has a network interface built by DAIHAN Scientific Co., 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 B4:EF:04:00:00:00 to B4:EF:04:FF:FF:FF.

OUI prefix: B4:EF:04
Hyphen form: B4-EF-04
MAC range: B4:EF:04:00:00:00 – B4:EF:04:FF:FF:FF
Addresses in block: 16,777,216
Organization: DAIHAN Scientific Co., Ltd.
Address: 326, Sinpyoungsukhwaro Wonju-si, Gangwon-do KR 26358
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 "DAIHAN Scientific Co., Ltd."
archived source →
2026-07-17Assigned to "DAIHAN Scientific Co., Ltd."

Nearby in the registry

The prefixes assigned immediately before and after B4:EF:04:

FAQ

Which company owns MAC address prefix B4:EF:04?: MAC address prefix B4:EF:04 is registered to DAIHAN Scientific Co., Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with B4:EF:04 has a network interface built by DAIHAN Scientific Co., Ltd..
What is the OUI B4:EF:04?: B4:EF:04 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to DAIHAN Scientific Co., Ltd.. It covers every address from B4:EF:04:00:00:00 to B4:EF:04:FF:FF:FF, or 16,777,216 addresses in total. It is also written B4-EF-04.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in B4:EF:04:00:00:00 that is B4:EF:04 — 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 DAIHAN Scientific Co., Ltd. located?: DAIHAN Scientific Co., Ltd. is listed at 326, Sinpyoungsukhwaro Wonju-si, Gangwon-do KR 26358 in the IEEE OUI registry entry for B4:EF:04. This is the address the organization registered with the IEEE, which may differ from its current operating address.