About MAC Address Lookup (OUI)

Identify the manufacturer from a MAC address OUI prefix. Part of the DevTools Surf developer suite. Browse more tools in the Networking collection.

Use Cases

• Network admins identifying unknown devices on corporate networks
• Security analysts tracing device manufacturers in traffic logs
• IoT developers verifying hardware vendor assignments
• Help desk staff identifying device types from DHCP lease tables

Tips

• Enter just the first 6 hex digits for OUI manufacturer lookup
• Use colons, hyphens, or no separators — all formats work
• Cross-reference unknown devices on your network by vendor

Fun Facts

• The IEEE has assigned over 40,000 OUI (Organizationally Unique Identifier) prefixes — Apple alone holds more than 600 OUI blocks for its devices.
• MAC addresses are 48 bits long, providing 281 trillion unique addresses — the format was defined in the original 1980 Ethernet specification by DEC, Intel, and Xerox.
• The 'locally administered' bit (second least significant bit of the first byte) lets organizations create private MAC addresses — Apple uses this for Wi-Fi privacy starting with iOS 14.

FAQ

What does the OUI tell me?

The manufacturer (Apple, Cisco, Dell, etc.). The first 3 bytes (6 hex digits) of a MAC address are the OUI — Organizationally Unique Identifier.

Can I identify a specific device?

Only the manufacturer. The remaining 3 bytes are device-unique but not globally registered; you can't find 'which specific iPhone'.

What about randomized MACs?

iPhones and Androids randomize MACs for privacy on Wi-Fi probes. The tool flags likely-randomized addresses (locally-administered bit set).

Is the database current?

Based on IEEE's public OUI database, updated regularly. New OUIs are added weekly; very-recent allocations may not appear until the next database sync.