Which company owns MAC address prefix D0:57:A1?

MAC address prefix D0:57:A1 is registered to Werma Signaltechnik GmbH & Co. KG in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:57:A1 has a network interface built by Werma Signaltechnik GmbH & Co. KG.

What is the OUI D0:57:A1?

D0:57:A1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Werma Signaltechnik GmbH & Co. KG. It covers every address from D0:57:A1:00:00:00 to D0:57:A1:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-57-A1.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in D0:57:A1:00:00:00 that is D0:57:A1 — 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 Werma Signaltechnik GmbH & Co. KG located?

Werma Signaltechnik GmbH & Co. KG is listed at Duerbheimer Strasse Rietheim-Weilheim DE 78604 in the IEEE OUI registry entry for D0:57:A1. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Werma Signaltechnik GmbH & Co. KG

MAC address prefix D0:57:A1 is registered to Werma Signaltechnik GmbH & Co. KG in the IEEE OUI registry. Any device whose MAC address begins with D0:57:A1 has a network interface built by Werma Signaltechnik GmbH & Co. KG. 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 D0:57:A1:00:00:00 to D0:57:A1:FF:FF:FF.

OUI prefix: D0:57:A1
Hyphen form: D0-57-A1
MAC range: D0:57:A1:00:00:00 – D0:57:A1:FF:FF:FF
Addresses in block: 16,777,216
Organization: Werma Signaltechnik GmbH & Co. KG
Address: Duerbheimer Strasse Rietheim-Weilheim DE 78604
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 "Werma Signaltechnik GmbH & Co. KG"
archived source →
2026-07-17Assigned to "Werma Signaltechnik GmbH & Co. KG"

Nearby in the registry

The prefixes assigned immediately before and after D0:57:A1:

FAQ

Which company owns MAC address prefix D0:57:A1?: MAC address prefix D0:57:A1 is registered to Werma Signaltechnik GmbH & Co. KG in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with D0:57:A1 has a network interface built by Werma Signaltechnik GmbH & Co. KG.
What is the OUI D0:57:A1?: D0:57:A1 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Werma Signaltechnik GmbH & Co. KG. It covers every address from D0:57:A1:00:00:00 to D0:57:A1:FF:FF:FF, or 16,777,216 addresses in total. It is also written D0-57-A1.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in D0:57:A1:00:00:00 that is D0:57:A1 — 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 Werma Signaltechnik GmbH & Co. KG located?: Werma Signaltechnik GmbH & Co. KG is listed at Duerbheimer Strasse Rietheim-Weilheim DE 78604 in the IEEE OUI registry entry for D0:57:A1. This is the address the organization registered with the IEEE, which may differ from its current operating address.