Which company owns MAC address prefix 90:DA:F9?

MAC address prefix 90:DA:F9 is registered to Siemens Rail Automation SAU in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 90:DA:F9 has a network interface built by Siemens Rail Automation SAU.

What is the OUI 90:DA:F9?

90:DA:F9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Siemens Rail Automation SAU. It covers every address from 90:DA:F9:00:00:00 to 90:DA:F9:FF:FF:FF, or 16,777,216 addresses in total. It is also written 90-DA-F9.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in 90:DA:F9:00:00:00 that is 90:DA:F9 — 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 Siemens Rail Automation SAU located?

Siemens Rail Automation SAU is listed at Ronda de Europa, 5 Tres Cantos ES 28760 in the IEEE OUI registry entry for 90:DA:F9. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Siemens Rail Automation SAU

MAC address prefix 90:DA:F9 is registered to Siemens Rail Automation SAU in the IEEE OUI registry. Any device whose MAC address begins with 90:DA:F9 has a network interface built by Siemens Rail Automation SAU. 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 90:DA:F9:00:00:00 to 90:DA:F9:FF:FF:FF.

OUI prefix: 90:DA:F9
Hyphen form: 90-DA-F9
MAC range: 90:DA:F9:00:00:00 – 90:DA:F9:FF:FF:FF
Addresses in block: 16,777,216
Organization: Siemens Rail Automation SAU
Address: Ronda de Europa, 5 Tres Cantos ES 28760
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 (1)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2026-07-17Assigned to "Siemens Rail Automation SAU"

Nearby in the registry

The prefixes assigned immediately before and after 90:DA:F9:

FAQ

Which company owns MAC address prefix 90:DA:F9?: MAC address prefix 90:DA:F9 is registered to Siemens Rail Automation SAU in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with 90:DA:F9 has a network interface built by Siemens Rail Automation SAU.
What is the OUI 90:DA:F9?: 90:DA:F9 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Siemens Rail Automation SAU. It covers every address from 90:DA:F9:00:00:00 to 90:DA:F9:FF:FF:FF, or 16,777,216 addresses in total. It is also written 90-DA-F9.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in 90:DA:F9:00:00:00 that is 90:DA:F9 — 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 Siemens Rail Automation SAU located?: Siemens Rail Automation SAU is listed at Ronda de Europa, 5 Tres Cantos ES 28760 in the IEEE OUI registry entry for 90:DA:F9. This is the address the organization registered with the IEEE, which may differ from its current operating address.