Which company owns MAC address prefix BC:A3:7F?

MAC address prefix BC:A3:7F is registered to Rail-Mil Sp. z o.o. Sp. K. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with BC:A3:7F has a network interface built by Rail-Mil Sp. z o.o. Sp. K..

What is the OUI BC:A3:7F?

BC:A3:7F is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Rail-Mil Sp. z o.o. Sp. K.. It covers every address from BC:A3:7F:00:00:00 to BC:A3:7F:FF:FF:FF, or 16,777,216 addresses in total. It is also written BC-A3-7F.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in BC:A3:7F:00:00:00 that is BC:A3:7F — 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 Rail-Mil Sp. z o.o. Sp. K. located?

Rail-Mil Sp. z o.o. Sp. K. is listed at Kosmatki 82 Warsaw PL 03-982 in the IEEE OUI registry entry for BC:A3:7F. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Rail-Mil Sp. z o.o. Sp. K.

MAC address prefix BC:A3:7F is registered to Rail-Mil Sp. z o.o. Sp. K. in the IEEE OUI registry. Any device whose MAC address begins with BC:A3:7F has a network interface built by Rail-Mil Sp. z o.o. Sp. K.. 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 BC:A3:7F:00:00:00 to BC:A3:7F:FF:FF:FF.

OUI prefix: BC:A3:7F
Hyphen form: BC-A3-7F
MAC range: BC:A3:7F:00:00:00 – BC:A3:7F:FF:FF:FF
Addresses in block: 16,777,216
Organization: Rail-Mil Sp. z o.o. Sp. K.
Address: Kosmatki 82 Warsaw PL 03-982
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.

2021-06-10Assigned to "Rail-Mil Sp. z o.o. Sp. K."
archived source →
2026-07-17Assigned to "Rail-Mil Sp. z o.o. Sp. K."

Nearby in the registry

The prefixes assigned immediately before and after BC:A3:7F:

FAQ

Which company owns MAC address prefix BC:A3:7F?: MAC address prefix BC:A3:7F is registered to Rail-Mil Sp. z o.o. Sp. K. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with BC:A3:7F has a network interface built by Rail-Mil Sp. z o.o. Sp. K..
What is the OUI BC:A3:7F?: BC:A3:7F is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Rail-Mil Sp. z o.o. Sp. K.. It covers every address from BC:A3:7F:00:00:00 to BC:A3:7F:FF:FF:FF, or 16,777,216 addresses in total. It is also written BC-A3-7F.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in BC:A3:7F:00:00:00 that is BC:A3:7F — 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 Rail-Mil Sp. z o.o. Sp. K. located?: Rail-Mil Sp. z o.o. Sp. K. is listed at Kosmatki 82 Warsaw PL 03-982 in the IEEE OUI registry entry for BC:A3:7F. This is the address the organization registered with the IEEE, which may differ from its current operating address.