Which company owns MAC address prefix A0:BF:A5?

MAC address prefix A0:BF:A5 is registered to CORESYS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:BF:A5 has a network interface built by CORESYS.

What is the OUI A0:BF:A5?

A0:BF:A5 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to CORESYS. It covers every address from A0:BF:A5:00:00:00 to A0:BF:A5:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-BF-A5.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A0:BF:A5:00:00:00 that is A0:BF:A5 — 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 CORESYS located?

CORESYS is listed at 267-1 Nonhyundong Gangnamgu Seoul KR 135-833 in the IEEE OUI registry entry for A0:BF:A5. This is the address the organization registered with the IEEE, which may differ from its current operating address.

CORESYS

MAC address prefix A0:BF:A5 is registered to CORESYS in the IEEE OUI registry. Any device whose MAC address begins with A0:BF:A5 has a network interface built by CORESYS. 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 A0:BF:A5:00:00:00 to A0:BF:A5:FF:FF:FF.

OUI prefix: A0:BF:A5
Hyphen form: A0-BF-A5
MAC range: A0:BF:A5:00:00:00 – A0:BF:A5:FF:FF:FF
Addresses in block: 16,777,216
Organization: CORESYS
Address: 267-1 Nonhyundong Gangnamgu Seoul KR 135-833
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 "CORESYS"
archived source →
2026-07-17Assigned to "CORESYS"

Nearby in the registry

The prefixes assigned immediately before and after A0:BF:A5:

FAQ

Which company owns MAC address prefix A0:BF:A5?: MAC address prefix A0:BF:A5 is registered to CORESYS in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:BF:A5 has a network interface built by CORESYS.
What is the OUI A0:BF:A5?: A0:BF:A5 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to CORESYS. It covers every address from A0:BF:A5:00:00:00 to A0:BF:A5:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-BF-A5.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A0:BF:A5:00:00:00 that is A0:BF:A5 — 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 CORESYS located?: CORESYS is listed at 267-1 Nonhyundong Gangnamgu Seoul KR 135-833 in the IEEE OUI registry entry for A0:BF:A5. This is the address the organization registered with the IEEE, which may differ from its current operating address.