Which company owns MAC address prefix 24:CF:21?

MAC address prefix 24:CF:21 is registered to Shenzhen State Micro Technology Co., Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 24:CF:21 has a network interface built by Shenzhen State Micro Technology Co., Ltd.

What is the OUI 24:CF:21?

24:CF:21 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Shenzhen State Micro Technology Co., Ltd. It covers every address from 24:CF:21:00:00:00 to 24:CF:21:FF:FF:FF, or 16,777,216 addresses in total. It is also written 24-CF-21.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 24:CF:21:00:00:00 that is 24:CF:21 — 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 Shenzhen State Micro Technology Co., Ltd located?

Shenzhen State Micro Technology Co., Ltd is listed at SSMEC Building2/F, Gao Xin Nan First Avenue, Hi-Tech Park South, Nanshan Shenzhen City Guangdong Province CN 518057 in the IEEE OUI registry entry for 24:CF:21. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Shenzhen State Micro Technology Co., Ltd

MAC address prefix 24:CF:21 is registered to Shenzhen State Micro Technology Co., Ltd in the IEEE OUI registry. Any device whose MAC address begins with 24:CF:21 has a network interface built by Shenzhen State Micro Technology 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 24:CF:21:00:00:00 to 24:CF:21:FF:FF:FF.

OUI prefix: 24:CF:21
Hyphen form: 24-CF-21
MAC range: 24:CF:21:00:00:00 – 24:CF:21:FF:FF:FF
Addresses in block: 16,777,216
Organization: Shenzhen State Micro Technology Co., Ltd
Address: SSMEC Building2/F, Gao Xin Nan First Avenue, Hi-Tech Park South, Nanshan Shenzhen City Guangdong Province CN 518057
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 "Shenzhen State Micro Technology Co., Ltd"
archived source →
2026-07-17Assigned to "Shenzhen State Micro Technology Co., Ltd"

Nearby in the registry

The prefixes assigned immediately before and after 24:CF:21:

FAQ

Which company owns MAC address prefix 24:CF:21?: MAC address prefix 24:CF:21 is registered to Shenzhen State Micro Technology Co., Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 24:CF:21 has a network interface built by Shenzhen State Micro Technology Co., Ltd.
What is the OUI 24:CF:21?: 24:CF:21 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Shenzhen State Micro Technology Co., Ltd. It covers every address from 24:CF:21:00:00:00 to 24:CF:21:FF:FF:FF, or 16,777,216 addresses in total. It is also written 24-CF-21.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 24:CF:21:00:00:00 that is 24:CF:21 — 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 Shenzhen State Micro Technology Co., Ltd located?: Shenzhen State Micro Technology Co., Ltd is listed at SSMEC Building2/F, Gao Xin Nan First Avenue, Hi-Tech Park South, Nanshan Shenzhen City Guangdong Province CN 518057 in the IEEE OUI registry entry for 24:CF:21. This is the address the organization registered with the IEEE, which may differ from its current operating address.