Which company owns MAC address prefix C4:E0:32?

MAC address prefix C4:E0:32 is registered to IEEE 1904.1 Working Group in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with C4:E0:32 has a network interface built by IEEE 1904.1 Working Group.

What is the OUI C4:E0:32?

C4:E0:32 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to IEEE 1904.1 Working Group. It covers every address from C4:E0:32:00:00:00 to C4:E0:32:FF:FF:FF, or 16,777,216 addresses in total. It is also written C4-E0-32.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in C4:E0:32:00:00:00 that is C4:E0:32 — 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 IEEE 1904.1 Working Group located?

IEEE 1904.1 Working Group is listed at 1351 Redwood Way, Petaluma CA US 94954 in the IEEE OUI registry entry for C4:E0:32. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does IEEE 1904.1 Working Group own?

IEEE 1904.1 Working Group holds 3 OUI prefixes in the IEEE registry, of which C4:E0:32 is one. A device made by IEEE 1904.1 Working Group could carry a MAC address from any of them.

IEEE 1904.1 Working Group

MAC address prefix C4:E0:32 is registered to IEEE 1904.1 Working Group in the IEEE OUI registry. Any device whose MAC address begins with C4:E0:32 has a network interface built by IEEE 1904.1 Working Group. 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 C4:E0:32:00:00:00 to C4:E0:32:FF:FF:FF.

OUI prefix: C4:E0:32
Hyphen form: C4-E0-32
MAC range: C4:E0:32:00:00:00 – C4:E0:32:FF:FF:FF
Addresses in block: 16,777,216
Organization: IEEE 1904.1 Working Group
Address: 1351 Redwood Way, Petaluma CA US 94954
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 IEEE 1904.1 Working Group

IEEE 1904.1 Working Group holds 3 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.

2016-07-29Assigned to "IEEE 1904.1 Working Group"
archived source →
2026-07-17Assigned to "IEEE 1904.1 Working Group"

Nearby in the registry

The prefixes assigned immediately before and after C4:E0:32:

FAQ

Which company owns MAC address prefix C4:E0:32?: MAC address prefix C4:E0:32 is registered to IEEE 1904.1 Working Group in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with C4:E0:32 has a network interface built by IEEE 1904.1 Working Group.
What is the OUI C4:E0:32?: C4:E0:32 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to IEEE 1904.1 Working Group. It covers every address from C4:E0:32:00:00:00 to C4:E0:32:FF:FF:FF, or 16,777,216 addresses in total. It is also written C4-E0-32.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in C4:E0:32:00:00:00 that is C4:E0:32 — 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 IEEE 1904.1 Working Group located?: IEEE 1904.1 Working Group is listed at 1351 Redwood Way, Petaluma CA US 94954 in the IEEE OUI registry entry for C4:E0:32. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does IEEE 1904.1 Working Group own?: IEEE 1904.1 Working Group holds 3 OUI prefixes in the IEEE registry, of which C4:E0:32 is one. A device made by IEEE 1904.1 Working Group could carry a MAC address from any of them.