Which company owns MAC address prefix 78:20:51?

MAC address prefix 78:20:51 is registered to TP-Link Systems Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 78:20:51 has a network interface built by TP-Link Systems Inc..

What is the OUI 78:20:51?

78:20:51 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TP-Link Systems Inc.. It covers every address from 78:20:51:00:00:00 to 78:20:51:FF:FF:FF, or 16,777,216 addresses in total. It is also written 78-20-51.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 78:20:51:00:00:00 that is 78:20:51 — 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 TP-Link Systems Inc. located?

TP-Link Systems Inc. is listed at 10 Mauchly Irvine CA US 92618 in the IEEE OUI registry entry for 78:20:51. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does TP-Link Systems Inc. own?

TP-Link Systems Inc. holds 43 OUI prefixes in the IEEE registry, of which 78:20:51 is one. A device made by TP-Link Systems Inc. could carry a MAC address from any of them.

TP-Link Systems Inc.

MAC address prefix 78:20:51 is registered to TP-Link Systems Inc. in the IEEE OUI registry. Any device whose MAC address begins with 78:20:51 has a network interface built by TP-Link Systems Inc.. 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 78:20:51:00:00:00 to 78:20:51:FF:FF:FF.

OUI prefix: 78:20:51
Hyphen form: 78-20-51
MAC range: 78:20:51:00:00:00 – 78:20:51:FF:FF:FF
Addresses in block: 16,777,216
Organization: TP-Link Systems Inc.
Address: 10 Mauchly Irvine CA US 92618
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 TP-Link Systems Inc.

TP-Link Systems Inc. holds 43 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.

2025-05-13Assigned to "TP-Link Systems Inc."
archived source →
2026-07-17Assigned to "TP-Link Systems Inc."

Nearby in the registry

The prefixes assigned immediately before and after 78:20:51:

FAQ

Which company owns MAC address prefix 78:20:51?: MAC address prefix 78:20:51 is registered to TP-Link Systems Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 78:20:51 has a network interface built by TP-Link Systems Inc..
What is the OUI 78:20:51?: 78:20:51 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TP-Link Systems Inc.. It covers every address from 78:20:51:00:00:00 to 78:20:51:FF:FF:FF, or 16,777,216 addresses in total. It is also written 78-20-51.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 78:20:51:00:00:00 that is 78:20:51 — 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 TP-Link Systems Inc. located?: TP-Link Systems Inc. is listed at 10 Mauchly Irvine CA US 92618 in the IEEE OUI registry entry for 78:20:51. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does TP-Link Systems Inc. own?: TP-Link Systems Inc. holds 43 OUI prefixes in the IEEE registry, of which 78:20:51 is one. A device made by TP-Link Systems Inc. could carry a MAC address from any of them.