Which company owns MAC address prefix 28:56:C1?

MAC address prefix 28:56:C1 is registered to Harman/Becker Automotive Systems GmbH in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 28:56:C1 has a network interface built by Harman/Becker Automotive Systems GmbH.

What is the OUI 28:56:C1?

28:56:C1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Harman/Becker Automotive Systems GmbH. It covers every address from 28:56:C1:00:00:00 to 28:56:C1:FF:FF:FF, or 16,777,216 addresses in total. It is also written 28-56-C1.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 28:56:C1:00:00:00 that is 28:56: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 Harman/Becker Automotive Systems GmbH located?

Harman/Becker Automotive Systems GmbH is listed at 15th Fl, 400 Atlantic Street Stamford CT US 06901 in the IEEE OUI registry entry for 28:56:C1. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Harman/Becker Automotive Systems GmbH own?

Harman/Becker Automotive Systems GmbH holds 10 OUI prefixes in the IEEE registry, of which 28:56:C1 is one. A device made by Harman/Becker Automotive Systems GmbH could carry a MAC address from any of them.

Harman/Becker Automotive Systems GmbH

MAC address prefix 28:56:C1 is registered to Harman/Becker Automotive Systems GmbH in the IEEE OUI registry. Any device whose MAC address begins with 28:56:C1 has a network interface built by Harman/Becker Automotive Systems GmbH. 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 28:56:C1:00:00:00 to 28:56:C1:FF:FF:FF.

OUI prefix: 28:56:C1
Hyphen form: 28-56-C1
MAC range: 28:56:C1:00:00:00 – 28:56:C1:FF:FF:FF
Addresses in block: 16,777,216
Organization: Harman/Becker Automotive Systems GmbH
Address: 15th Fl, 400 Atlantic Street Stamford CT US 06901
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 Harman/Becker Automotive Systems GmbH

Harman/Becker Automotive Systems GmbH holds 10 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (3)

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 "Harman International"
archived source →
2020-03-21Renamed from "Harman International" to "Harman/Becker Automotive Systems GmbH"
archived source →
2026-07-17Assigned to "Harman/Becker Automotive Systems GmbH"

Nearby in the registry

The prefixes assigned immediately before and after 28:56:C1:

FAQ

Which company owns MAC address prefix 28:56:C1?: MAC address prefix 28:56:C1 is registered to Harman/Becker Automotive Systems GmbH in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 28:56:C1 has a network interface built by Harman/Becker Automotive Systems GmbH.
What is the OUI 28:56:C1?: 28:56:C1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Harman/Becker Automotive Systems GmbH. It covers every address from 28:56:C1:00:00:00 to 28:56:C1:FF:FF:FF, or 16,777,216 addresses in total. It is also written 28-56-C1.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 28:56:C1:00:00:00 that is 28:56: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 Harman/Becker Automotive Systems GmbH located?: Harman/Becker Automotive Systems GmbH is listed at 15th Fl, 400 Atlantic Street Stamford CT US 06901 in the IEEE OUI registry entry for 28:56:C1. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Harman/Becker Automotive Systems GmbH own?: Harman/Becker Automotive Systems GmbH holds 10 OUI prefixes in the IEEE registry, of which 28:56:C1 is one. A device made by Harman/Becker Automotive Systems GmbH could carry a MAC address from any of them.