DevKit

MAC Address Lookup: Find the Vendor (OUI)

Paste one or many MAC addresses in any notation — or the output of arp -a or ip neigh — to see the vendor, the assigned block, and whether each address is unicast, multicast, universal or randomized.

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About the MAC Address Lookup

The first half of a MAC address (EUI-48) is assigned by the IEEE Registration Authority. A manufacturer buys a block — an MA-L (the classic 24-bit OUI, 16 million addresses), an MA-M (28 bits, 1 million) or an MA-S (36 bits, 4,096) — and numbers its network interfaces inside it. The lookup searches the longest matching prefix first, so an address inside a small MA-S block is reported with its real owner and not with the owner of the enclosing 24-bit block. The registry data is stored on this site and loaded into your browser once; the addresses you type are not sent anywhere. The date of the data is shown under the result.

Two bits of the first byte have a meaning of their own. The lowest bit (I/G) tells unicast from multicast: 01:00:5E… carries IPv4 multicast, 33:33… IPv6 multicast and FF:FF:FF:FF:FF:FF is the broadcast address. The next bit (U/L) marks locally administered addresses: when the second hex digit is 2, 6, A or E, the address was not assigned by a manufacturer. That is what iOS, Android, Windows and macOS do when they use a private (randomized) Wi-Fi address, and what virtual machines, containers and VPN adapters generate — such addresses have no vendor, and the tool says so instead of guessing.

Addresses are accepted with colons, hyphens, Cisco dots (001a.2b3c.4d5e) or no separator, with or without leading zeros as printed by macOS arp -a, and as a prefix of six or more digits. Pasted text is scanned for addresses, so the output of arp -a, ip neigh or a switch's MAC table can be pasted as it is. Well-known special addresses are recognised: VRRP and HSRP virtual routers, spanning tree, LLDP, and the default prefixes of Docker, QEMU/KVM, VMware, Hyper-V and VirtualBox. A reverse search lists the prefixes registered to a vendor name.

How to use it

  1. Paste MAC addresses, one per line, or the output of arp -a / ip neigh.
  2. Read the vendor and the type of every address in the results table.
  3. Click a row to see the details: all notations with copy buttons, the address bits, the IPv6 link-local address.
  4. Type a company name in the vendor search to list its prefixes.
  5. Copy the table as TSV or download it as CSV.

Frequently asked questions

Why does my phone's MAC address have no vendor?
Phones and laptops use a private, randomized MAC address for each Wi-Fi network to prevent tracking. These addresses have the locally-administered bit set — the second hex digit is 2, 6, A or E — and are not in the IEEE registry. The real address is shown in the device settings when the feature is switched off.
What is an OUI?
The Organizationally Unique Identifier is the 24-bit number the IEEE assigns to a manufacturer; it is the first three bytes of the MAC addresses of its products. Smaller blocks of 28 and 36 bits (MA-M and MA-S) exist for companies that need fewer addresses.
Can a MAC address identify the exact device model?
No. It names the organization that registered the block, which is often the maker of the network chip or module (Espressif, Intel, Murata) and not the brand on the box. MAC addresses can also be changed in software.
How current is the vendor database?
It is a copy of the public IEEE registries (MA-L, MA-M, MA-S), built into the site; its date is shown under the result. Blocks assigned after that date are reported as not found.

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