Which company owns MAC address prefix 40:9B:CD?

MAC address prefix 40:9B:CD is registered to D-Link International in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 40:9B:CD has a network interface built by D-Link International.

What is the OUI 40:9B:CD?

40:9B:CD is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to D-Link International. It covers every address from 40:9B:CD:00:00:00 to 40:9B:CD:FF:FF:FF, or 16,777,216 addresses in total. It is also written 40-9B-CD.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 40:9B:CD:00:00:00 that is 40:9B:CD — 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 D-Link International located?

D-Link International is listed at 1 Internal Business Park, #03-12,The Synergy, Singapore Singapore Singapore SG 609917 in the IEEE OUI registry entry for 40:9B:CD. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does D-Link International own?

D-Link International holds 60 OUI prefixes in the IEEE registry, of which 40:9B:CD is one. A device made by D-Link International could carry a MAC address from any of them.

D-Link International

MAC address prefix 40:9B:CD is registered to D-Link International in the IEEE OUI registry. Any device whose MAC address begins with 40:9B:CD has a network interface built by D-Link International. 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 40:9B:CD:00:00:00 to 40:9B:CD:FF:FF:FF.

OUI prefix: 40:9B:CD
Hyphen form: 40-9B-CD
MAC range: 40:9B:CD:00:00:00 – 40:9B:CD:FF:FF:FF
Addresses in block: 16,777,216
Organization: D-Link International
Address: 1 Internal Business Park, #03-12,The Synergy, Singapore Singapore Singapore SG 609917
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 D-Link International

D-Link International holds 60 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.

2017-09-08Assigned to "D-Link International"
archived source →
2026-07-17Assigned to "D-Link International"

Nearby in the registry

The prefixes assigned immediately before and after 40:9B:CD:

FAQ

Which company owns MAC address prefix 40:9B:CD?: MAC address prefix 40:9B:CD is registered to D-Link International in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 40:9B:CD has a network interface built by D-Link International.
What is the OUI 40:9B:CD?: 40:9B:CD is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to D-Link International. It covers every address from 40:9B:CD:00:00:00 to 40:9B:CD:FF:FF:FF, or 16,777,216 addresses in total. It is also written 40-9B-CD.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 40:9B:CD:00:00:00 that is 40:9B:CD — 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 D-Link International located?: D-Link International is listed at 1 Internal Business Park, #03-12,The Synergy, Singapore Singapore Singapore SG 609917 in the IEEE OUI registry entry for 40:9B:CD. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does D-Link International own?: D-Link International holds 60 OUI prefixes in the IEEE registry, of which 40:9B:CD is one. A device made by D-Link International could carry a MAC address from any of them.