MAC Analyzer
Split a MAC address into its OUI and NIC bytes, and see what the U/L and I/G bits mean. It decodes structure only and does not name the manufacturer.
Every network interface has a 48-bit MAC address, and its structure says a few things before you look up who made the hardware. The first three bytes are the vendor's OUI, and two bits in the first byte say how the address was assigned and who it targets.
This runs in your browser. Nothing you type or open is uploaded.
How to read it
Type an address in any common format. The U/L bit says whether it was burned in at the factory or set in software, such as a VM NIC, a VPN adapter, or a phone randomizing its Wi-Fi address. The I/G bit says whether it targets one device or a group.
It does not name the vendor. Look the OUI up in the IEEE registry for that. A locally administered address will not be in the registry at all.
Sources
- IEEE Registration Authority: Search for an Assignment. The IEEE's own public search tool for OUI/MA-L assignments. Paste the OUI this page decodes into its lookup form to find the organization it was actually issued to, the one question this tool deliberately doesn't answer itself.
- IEEE Public OUI Listing (oui.txt). The Registration Authority's own raw, downloadable listing of every OUI assignment and the organization behind it: the authoritative source behind any vendor-lookup tool, useful for bulk or offline lookups against many OUIs at once rather than one at a time.
Worth using too
- Wireshark OUI Lookup Tool. A free, single-box lookup built and maintained by the Wireshark Foundation, wrapping the same IEEE-sourced OUI data in a much friendlier search than the Registration Authority's own multi-field web form: the faster first stop for a one-off vendor lookup once this page has decoded the OUI.