Identify the manufacturer behind any MAC address using the IEEE MA-L OUI registry. Paste any format — colons, dashes, dots, or plain hex. All lookups run entirely in your browser.
Enter a MAC address above to look up its vendor
A MAC address (Media Access Control address) is a 48-bit hardware identifier assigned to a network interface controller (NIC). It is represented as six pairs of hexadecimal digits — for example, A4:C3:F0:12:34:56 — separated by colons, dashes, or dots depending on the operating system or vendor tool.
MAC addresses operate at Layer 2 (the data link layer) of the OSI model. Switches use MAC addresses to forward frames within a local network segment, while IP addresses handle routing between networks. Unlike IP addresses, MAC addresses are not routed across the internet — they are local to the network segment.
The 48-bit address is divided into two halves:
An OUI (Organisationally Unique Identifier) is a 24-bit number assigned by the IEEE Registration Authority to organisations that manufacture network interfaces. When a company wants to produce Ethernet cards, Wi-Fi adapters, or any device with a MAC address, it purchases an OUI block from the IEEE and uses those first three bytes for all interfaces it manufactures.
The IEEE publishes the full MA-L (MAC Address Block Large) registry as a public dataset, which is what powers this tool. Each OUI block gives an organisation 16.7 million unique MAC addresses (the remaining 24 bits). Well-known OUI holders include Apple (A8:86:DD), Cisco (00:00:0C), and VMware (00:0C:29).
The second-least-significant bit of the first byte of a MAC address is the U/L bit (Universal/Local). When this bit is 0, the address is universally administered — meaning it was assigned by the manufacturer and is globally unique. When it is 1, the address is locally administered — meaning it was assigned by software and has no OUI entry.
Locally administered MACs appear in several common scenarios:
If you see a locally administered MAC on your network, it is likely a VM, container, VPN client, or a device using MAC randomisation.
The least-significant bit of the first byte is the I/G bit (Individual/Group). When it is 0, the address is a unicast address targeting a single interface. When it is 1, the address is a multicast address targeting a group of interfaces simultaneously.
Common multicast MAC ranges include:
FF:FF:FF:FF:FF:FF — broadcast, targets all devices on the segment01:00:5E:xx:xx:xx — IPv4 multicast (IANA assigned)33:33:xx:xx:xx:xx — IPv6 multicast (RFC 2464)01:80:C2:xx:xx:xx — IEEE 802.1D spanning tree protocolMulticast addresses have no OUI vendor because they are not assigned to manufacturers — they identify address groups rather than physical hardware.
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