MAC Vendor Lookup
Identify device manufacturers from MAC addresses using the IEEE OUI database. Paste multiple addresses for bulk lookup.
Vendor information will appear here...
Summary
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What is a MAC Vendor Lookup?
The first three bytes (24 bits) of every globally administered MAC address form the OUI (Organizationally Unique Identifier), assigned by the IEEE to hardware manufacturers. By looking up the OUI, you can identify which company manufactured a network device — useful for network audits, intrusion detection, and troubleshooting unknown devices on your network.
The IEEE publishes the official OUI registry at standards.ieee.org. This tool queries that database to match the first 3 bytes of any MAC address to its registered manufacturer.
How to Use This Tool
- Enter a MAC address in any format (colons, hyphens, dots, or no separator).
- Click Lookup or press Enter.
- The manufacturer name, OUI prefix, and additional details are displayed.
What You Can Learn from MAC Vendor Lookup
- Unknown devices on your network — Identify whether an unfamiliar device is a phone (Apple, Samsung), router (Cisco, Ubiquiti), IoT device, or potential intruder
- Virtual machines — VMware (
00:50:56), VirtualBox (08:00:27), and QEMU (52:54:00) have recognizable OUI prefixes - Network inventory — Categorize devices by manufacturer for asset management
- Security auditing — Flag unexpected vendor types (e.g., consumer devices on a corporate network)
- Wireless surveys — Identify client device manufacturers from AP association tables
Limitations of OUI Lookup
- Locally administered MACs (bit 2 of byte 1 set to 1) are not IEEE-assigned and won't return a vendor
- MAC randomization (enabled by default on modern iOS and Android for Wi-Fi scanning) generates locally administered random MACs that cannot be traced to a manufacturer
- The OUI tells you the NIC manufacturer, not the device brand — a Dell laptop might have an Intel NIC
Frequently Asked Questions
Several reasons: (1) The MAC is locally administered (bit 2 of byte 1 is set) — these aren't in the IEEE registry. (2) The device uses MAC randomization — modern phones randomize their MAC when scanning for Wi-Fi networks. (3) The OUI is registered but the registration is marked private in the IEEE database. (4) The OUI database hasn't been updated recently enough to include a very new manufacturer assignment.
The IEEE updates their OUI registry continuously as new manufacturers register. Our database is regularly synchronized with the IEEE public registry. If you find a newly registered OUI that doesn't resolve, it may not be in the current snapshot yet.
Not from the OUI alone — you can only identify the manufacturer. Some manufacturers use specific OUI blocks for product lines, and with additional context (network behavior, open ports, DHCP fingerprinting) you can narrow it down. Tools like Nmap's OS detection and Fingerbank provide more detailed device identification beyond OUI lookup.
MAC randomization is a privacy feature where devices generate a random MAC address for Wi-Fi scanning and (increasingly) connections. Apple enabled it by default in iOS 14, Android 10 added it, and Windows 10 includes it. Randomized MACs have bit 2 of byte 1 set (locally administered), so they return no vendor. This protects users from being tracked across locations via their hardware MAC address.
The IEEE offers three sizes of MAC address blocks: MA-L (OUI, /24 prefix — 16 million addresses), MA-M (medium, /28 prefix — 1 million addresses), and MA-S (small, /36 prefix — 4,096 addresses). Larger manufacturers buy MA-L blocks. Smaller companies or those needing fewer MACs use MA-M or MA-S. All are queryable by OUI prefix, though the lookup granularity differs.