MB Networks
TOOL-18 · Network
MAC vendor lookup
Identify the manufacturer of any network device from its MAC address via the IEEE OUI database.
Examples
How it works: The first 3 octets (24 bits) of a MAC address form the OUI (Organizationally Unique Identifier), assigned by the IEEE to manufacturers. Lookups run entirely in your browser against the bundled IEEE MA-L OUI database (~39,000 entries). No data is sent anywhere.
How a MAC address identifies a manufacturer
The first three octets of a MAC address (the OUI, Organizationally Unique Identifier) are assigned by the IEEE to a specific manufacturer and never change across that vendor's devices — the last three octets are unique to the individual device. Looking up the OUI tells you who made the network interface, which is often enough to identify an unlabeled device on your network (a Raspberry Pi, a specific NAS vendor, a phone manufacturer) without any other information.
Why this runs entirely offline
The OUI database is a bundled local file, not a live lookup against IEEE's servers — so this works without a network request and won't leak which devices you're investigating to any third party. The tradeoff is the database is a point-in-time snapshot; very recently registered OUIs may not be included yet.
Can a MAC address tell me the exact device model, not just the manufacturer?
No — the OUI identifies only the manufacturer (e.g. Apple, Raspberry Pi Foundation, TP-Link), not the specific model or device. Some larger vendors also register multiple OUI blocks for different product lines, but this tool can't distinguish between them from the MAC alone.
Why does my device show a “randomized” or unrecognized MAC address?
Modern phones and laptops (iOS, Android, Windows) increasingly randomize their MAC address per network by default, specifically to prevent this kind of tracking/identification. A randomized MAC won't match any real vendor's OUI in the database, which is the intended privacy behavior working as designed, not a lookup failure.
Does this tool send my MAC address anywhere?
No — the OUI database is a local file bundled with the page, and the lookup runs entirely in your browser with zero network requests.
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Open →Data from the IEEE MA-L OUI registry · SysAdmin Toolbelt