// Tool
MAC / OUI Vendor Lookup
Look up the vendor for a MAC address or 24-bit OUI prefix. Vendor data from api.macvendors.com (IEEE OUI registry, queried live).
Try:
Frequently Asked Questions
What is an OUI?
The Organizationally Unique Identifier is the first 24 bits (first three octets) of a MAC address. The IEEE assigns it to a manufacturer, so it identifies who made the interface.
What is a locally administered MAC address?
One where the second-least-significant bit of the first octet is set, meaning software or an admin assigned it rather than the vendor burning it in — common with randomized Wi-Fi MACs and virtual interfaces.
How do I tell a multicast MAC from a unicast one?
The least-significant bit of the first octet: 0 means unicast (one recipient), 1 means multicast (a group). Broadcast (ff:ff:ff:ff:ff:ff) is the special all-ones case.
