Which company owns MAC address prefix 00:18:7B?

MAC address prefix 00:18:7B is registered to 4NSYS Co. Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 00:18:7B has a network interface built by 4NSYS Co. Ltd..

What is the OUI 00:18:7B?

00:18:7B is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to 4NSYS Co. Ltd.. It covers every address from 00:18:7B:00:00:00 to 00:18:7B:FF:FF:FF, or 16,777,216 addresses in total. It is also written 00-18-7B.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 00:18:7B:00:00:00 that is 00:18:7B — 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 4NSYS Co. Ltd. located?

4NSYS Co. Ltd. is listed at 3F, Hana Bldg Guro-Gu Seoul KR 152-100 in the IEEE OUI registry entry for 00:18:7B. This is the address the organization registered with the IEEE, which may differ from its current operating address.

4NSYS Co. Ltd.

MAC address prefix 00:18:7B is registered to 4NSYS Co. Ltd. in the IEEE OUI registry. Any device whose MAC address begins with 00:18:7B has a network interface built by 4NSYS 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 00:18:7B:00:00:00 to 00:18:7B:FF:FF:FF.

OUI prefix: 00:18:7B
Hyphen form: 00-18-7B
MAC range: 00:18:7B:00:00:00 – 00:18:7B:FF:FF:FF
Addresses in block: 16,777,216
Organization: 4NSYS Co. Ltd.
Address: 3F, Hana Bldg Guro-Gu Seoul KR 152-100
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 "4NSYS Co. Ltd."
archived source →
2026-07-17Assigned to "4NSYS Co. Ltd."

Nearby in the registry

The prefixes assigned immediately before and after 00:18:7B:

FAQ

Which company owns MAC address prefix 00:18:7B?: MAC address prefix 00:18:7B is registered to 4NSYS Co. Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 00:18:7B has a network interface built by 4NSYS Co. Ltd..
What is the OUI 00:18:7B?: 00:18:7B is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to 4NSYS Co. Ltd.. It covers every address from 00:18:7B:00:00:00 to 00:18:7B:FF:FF:FF, or 16,777,216 addresses in total. It is also written 00-18-7B.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 00:18:7B:00:00:00 that is 00:18:7B — 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 4NSYS Co. Ltd. located?: 4NSYS Co. Ltd. is listed at 3F, Hana Bldg Guro-Gu Seoul KR 152-100 in the IEEE OUI registry entry for 00:18:7B. This is the address the organization registered with the IEEE, which may differ from its current operating address.