Which company owns MAC address prefix F4:49:EF?

MAC address prefix F4:49:EF is registered to EMSTONE in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with F4:49:EF has a network interface built by EMSTONE.

What is the OUI F4:49:EF?

F4:49:EF is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to EMSTONE. It covers every address from F4:49:EF:00:00:00 to F4:49:EF:FF:FF:FF, or 16,777,216 addresses in total. It is also written F4-49-EF.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in F4:49:EF:00:00:00 that is F4:49:EF — 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 EMSTONE located?

EMSTONE is listed at #1201, Byeoksan Digital Valley 3rd, 271, Digital-ro Guro-Gu Seoul KR 08381 in the IEEE OUI registry entry for F4:49:EF. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does EMSTONE own?

EMSTONE holds 2 OUI prefixes in the IEEE registry, of which F4:49:EF is one. A device made by EMSTONE could carry a MAC address from any of them.

EMSTONE

MAC address prefix F4:49:EF is registered to EMSTONE in the IEEE OUI registry. Any device whose MAC address begins with F4:49:EF has a network interface built by EMSTONE. 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 F4:49:EF:00:00:00 to F4:49:EF:FF:FF:FF.

OUI prefix: F4:49:EF
Hyphen form: F4-49-EF
MAC range: F4:49:EF:00:00:00 – F4:49:EF:FF:FF:FF
Addresses in block: 16,777,216
Organization: EMSTONE
Address: #1201, Byeoksan Digital Valley 3rd, 271, Digital-ro Guro-Gu Seoul KR 08381
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 EMSTONE

EMSTONE holds 2 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

24:FA:D6

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2017-09-08Assigned to "EMSTONE"
archived source →
2026-07-17Assigned to "EMSTONE"

Nearby in the registry

The prefixes assigned immediately before and after F4:49:EF:

FAQ

Which company owns MAC address prefix F4:49:EF?: MAC address prefix F4:49:EF is registered to EMSTONE in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with F4:49:EF has a network interface built by EMSTONE.
What is the OUI F4:49:EF?: F4:49:EF is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to EMSTONE. It covers every address from F4:49:EF:00:00:00 to F4:49:EF:FF:FF:FF, or 16,777,216 addresses in total. It is also written F4-49-EF.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in F4:49:EF:00:00:00 that is F4:49:EF — 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 EMSTONE located?: EMSTONE is listed at #1201, Byeoksan Digital Valley 3rd, 271, Digital-ro Guro-Gu Seoul KR 08381 in the IEEE OUI registry entry for F4:49:EF. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does EMSTONE own?: EMSTONE holds 2 OUI prefixes in the IEEE registry, of which F4:49:EF is one. A device made by EMSTONE could carry a MAC address from any of them.