Which company owns MAC address prefix 78:C5:7D?

MAC address prefix 78:C5:7D is registered to Zyxel Communications Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 78:C5:7D has a network interface built by Zyxel Communications Corporation.

What is the OUI 78:C5:7D?

78:C5:7D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Zyxel Communications Corporation. It covers every address from 78:C5:7D:00:00:00 to 78:C5:7D:FF:FF:FF, or 16,777,216 addresses in total. It is also written 78-C5-7D.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 78:C5:7D:00:00:00 that is 78:C5:7D — 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 Zyxel Communications Corporation located?

Zyxel Communications Corporation is listed at No. 6 Innovation Road II, Science Park Hsichu Taiwan TW 300 in the IEEE OUI registry entry for 78:C5:7D. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Zyxel Communications Corporation own?

Zyxel Communications Corporation holds 71 OUI prefixes in the IEEE registry, of which 78:C5:7D is one. A device made by Zyxel Communications Corporation could carry a MAC address from any of them.

Zyxel Communications Corporation

MAC address prefix 78:C5:7D is registered to Zyxel Communications Corporation in the IEEE OUI registry. Any device whose MAC address begins with 78:C5:7D has a network interface built by Zyxel Communications Corporation. 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:C5:7D:00:00:00 to 78:C5:7D:FF:FF:FF.

OUI prefix: 78:C5:7D
Hyphen form: 78-C5-7D
MAC range: 78:C5:7D:00:00:00 – 78:C5:7D:FF:FF:FF
Addresses in block: 16,777,216
Organization: Zyxel Communications Corporation
Address: No. 6 Innovation Road II, Science Park Hsichu Taiwan TW 300
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 Zyxel Communications Corporation

Zyxel Communications Corporation holds 71 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.

2022-07-11Assigned to "Zyxel Communications Corporation"
archived source →
2026-07-17Assigned to "Zyxel Communications Corporation"

Nearby in the registry

The prefixes assigned immediately before and after 78:C5:7D:

FAQ

Which company owns MAC address prefix 78:C5:7D?: MAC address prefix 78:C5:7D is registered to Zyxel Communications Corporation in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 78:C5:7D has a network interface built by Zyxel Communications Corporation.
What is the OUI 78:C5:7D?: 78:C5:7D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Zyxel Communications Corporation. It covers every address from 78:C5:7D:00:00:00 to 78:C5:7D:FF:FF:FF, or 16,777,216 addresses in total. It is also written 78-C5-7D.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 78:C5:7D:00:00:00 that is 78:C5:7D — 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 Zyxel Communications Corporation located?: Zyxel Communications Corporation is listed at No. 6 Innovation Road II, Science Park Hsichu Taiwan TW 300 in the IEEE OUI registry entry for 78:C5:7D. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Zyxel Communications Corporation own?: Zyxel Communications Corporation holds 71 OUI prefixes in the IEEE registry, of which 78:C5:7D is one. A device made by Zyxel Communications Corporation could carry a MAC address from any of them.