Donaldson R F MAC Address Lookup
Find out which company made a network card or device from its MAC address, using the IEEE's official vendor registry.
How MAC address lookup works
The first half of a MAC address is assigned by the IEEE to the manufacturer — the OUI (Organizationally Unique Identifier). This tool checks the address against the IEEE's three public registries: MA-L (24-bit blocks, the classic OUI), MA-M (28-bit) and MA-S (36-bit) — the larger blocks are shared between several companies, so for those you need the full address. Accepted formats include 00:1A:2B:3C:4D:5E, 00-1A-2B-3C-4D-5E, 001A.2B3C.4D5E and 001A2B3C4D5E; six digits are enough to look up the OUI. Modern phones and laptops often use a random “locally administered” MAC address for privacy, which has no manufacturer at all.
Data source: IEEE Registration Authority public registry — standards.ieee.org/products-programs/regauth (files oui.csv, mam.csv, oui36.csv from standards-oui.ieee.org), downloaded in September 2026. New assignments appear over time, so a very new device may not be listed. Only the vendor names are kept here and each lookup fetches one small file, on demand.