Which company owns MAC address prefix A4:F3:C1?

MAC address prefix A4:F3:C1 is registered to Open Source Robotics Foundation, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A4:F3:C1 has a network interface built by Open Source Robotics Foundation, Inc..

What is the OUI A4:F3:C1?

A4:F3:C1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Open Source Robotics Foundation, Inc.. It covers every address from A4:F3:C1:00:00:00 to A4:F3:C1:FF:FF:FF, or 16,777,216 addresses in total. It is also written A4-F3-C1.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A4:F3:C1:00:00:00 that is A4:F3:C1 — 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 Open Source Robotics Foundation, Inc. located?

Open Source Robotics Foundation, Inc. is listed at 419 N Shoreline Blvd Mountain View CA US 94043 in the IEEE OUI registry entry for A4:F3:C1. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Open Source Robotics Foundation, Inc.

MAC address prefix A4:F3:C1 is registered to Open Source Robotics Foundation, Inc. in the IEEE OUI registry. Any device whose MAC address begins with A4:F3:C1 has a network interface built by Open Source Robotics Foundation, 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 A4:F3:C1:00:00:00 to A4:F3:C1:FF:FF:FF.

OUI prefix: A4:F3:C1
Hyphen form: A4-F3-C1
MAC range: A4:F3:C1:00:00:00 – A4:F3:C1:FF:FF:FF
Addresses in block: 16,777,216
Organization: Open Source Robotics Foundation, Inc.
Address: 419 N Shoreline Blvd Mountain View CA US 94043
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 "Open Source Robotics Foundation, Inc."
archived source →
2026-07-17Assigned to "Open Source Robotics Foundation, Inc."

Nearby in the registry

The prefixes assigned immediately before and after A4:F3:C1:

FAQ

Which company owns MAC address prefix A4:F3:C1?: MAC address prefix A4:F3:C1 is registered to Open Source Robotics Foundation, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A4:F3:C1 has a network interface built by Open Source Robotics Foundation, Inc..
What is the OUI A4:F3:C1?: A4:F3:C1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Open Source Robotics Foundation, Inc.. It covers every address from A4:F3:C1:00:00:00 to A4:F3:C1:FF:FF:FF, or 16,777,216 addresses in total. It is also written A4-F3-C1.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A4:F3:C1:00:00:00 that is A4:F3:C1 — 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 Open Source Robotics Foundation, Inc. located?: Open Source Robotics Foundation, Inc. is listed at 419 N Shoreline Blvd Mountain View CA US 94043 in the IEEE OUI registry entry for A4:F3:C1. This is the address the organization registered with the IEEE, which may differ from its current operating address.