Which company owns MAC address prefix A8:B9:B3?

MAC address prefix A8:B9:B3 is registered to ESSYS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A8:B9:B3 has a network interface built by ESSYS.

What is the OUI A8:B9:B3?

A8:B9:B3 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ESSYS. It covers every address from A8:B9:B3:00:00:00 to A8:B9:B3:FF:FF:FF, or 16,777,216 addresses in total. It is also written A8-B9-B3.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A8:B9:B3:00:00:00 that is A8:B9:B3 — 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 ESSYS located?

ESSYS is listed at Daerung Post Tower 5 15F Seoul Gasan-Dong, Geumchen-gu KR 153-702 in the IEEE OUI registry entry for A8:B9:B3. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does ESSYS own?

ESSYS holds 5 OUI prefixes in the IEEE registry, of which A8:B9:B3 is one. A device made by ESSYS could carry a MAC address from any of them.

ESSYS

MAC address prefix A8:B9:B3 is registered to ESSYS in the IEEE OUI registry. Any device whose MAC address begins with A8:B9:B3 has a network interface built by ESSYS. 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 A8:B9:B3:00:00:00 to A8:B9:B3:FF:FF:FF.

OUI prefix: A8:B9:B3
Hyphen form: A8-B9-B3
MAC range: A8:B9:B3:00:00:00 – A8:B9:B3:FF:FF:FF
Addresses in block: 16,777,216
Organization: ESSYS
Address: Daerung Post Tower 5 15F Seoul Gasan-Dong, Geumchen-gu KR 153-702
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.

Other prefixes from ESSYS

ESSYS holds 5 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

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 "ESSYS"
archived source →
2026-07-17Assigned to "ESSYS"

Nearby in the registry

The prefixes assigned immediately before and after A8:B9:B3:

FAQ

Which company owns MAC address prefix A8:B9:B3?: MAC address prefix A8:B9:B3 is registered to ESSYS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A8:B9:B3 has a network interface built by ESSYS.
What is the OUI A8:B9:B3?: A8:B9:B3 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to ESSYS. It covers every address from A8:B9:B3:00:00:00 to A8:B9:B3:FF:FF:FF, or 16,777,216 addresses in total. It is also written A8-B9-B3.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A8:B9:B3:00:00:00 that is A8:B9:B3 — 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 ESSYS located?: ESSYS is listed at Daerung Post Tower 5 15F Seoul Gasan-Dong, Geumchen-gu KR 153-702 in the IEEE OUI registry entry for A8:B9:B3. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does ESSYS own?: ESSYS holds 5 OUI prefixes in the IEEE registry, of which A8:B9:B3 is one. A device made by ESSYS could carry a MAC address from any of them.