MAC Address Vendor Lookup
NetworkFree online MAC OUI vendor lookup — identify the manufacturer behind any MAC address using the IEEE database. Spot unknown devices on your local network in seconds. Runs locally, no upload, no signup, no registration.
B8:27:EBAbout MAC Address Vendor Lookup
The first 3 bytes of every MAC address form the OUI (Organizationally Unique Identifier), assigned by the IEEE to network card vendors. The OUI lets you look up which manufacturer made a card. This tool matches the MAC you enter against a built-in OUI database locally in your browser to identify its vendor, helping you recognize unknown devices during network troubleshooting. Lookups are offline and the MAC is never uploaded. Tip: Bookmark this tool for quick access during network troubleshooting. All queries are made directly from your browser — no command-line tools required.
How to Use
- Open the MAC Address Vendor Lookup tool page
- Enter or paste your data into the input area
- View the real-time results and use the copy button to get the output
Use Cases
- Identify unknown devices — See an unfamiliar MAC in an ARP table or DHCP lease and look up the vendor to guess the device.
- Investigate access — Check whether a terminal on a switch port comes from the expected vendor and spot suspicious hardware.
- Asset inventory — Match device MACs to vendors in bulk to help build a network asset list.
- Forensic analysis — Extract MACs from captures and combine vendor info to trace communicating devices.
- Virtual vs physical — Tell whether a MAC belongs to a VM vendor (VMware, QEMU) or a physical card.
- DHCP lease audit — Cross-reference vendor OUIs against DHCP lease logs to flag unauthorized devices on the network.
- Penetration testing — Identify the NIC vendor of a discovered target from its MAC to profile the hardware stack.
FAQ
What is an OUI?
The OUI (Organizationally Unique Identifier) is a 24-bit prefix the IEEE assigns to vendors — the first 3 bytes of a MAC. All of a vendor's cards share its OUI, so the vendor can be looked up from it.
Why can't some MACs be matched to a vendor?
It may be a locally-administered address (LAA, with bit 2 of the first byte set) defined by a user and tied to no vendor, or the OUI may be new and absent from the built-in database.
Do I need the full MAC to find the vendor?
No. Only the first 3 bytes (the OUI) determine the vendor; the last 3 bytes are the vendor's internal serial and are irrelevant to identification.
Can virtual machine MACs be looked up?
Yes. VMware, VirtualBox, QEMU/KVM, and Xen all have dedicated OUI prefixes, so matching one of these usually means a virtual adapter.
Want to generate a MAC for a vendor instead?
Use our MAC Generator tool: fix a vendor OUI prefix and randomize the last three bytes.
Any browser compatibility requirements?
This tool works in all modern browsers (Chrome, Firefox, Edge, Safari). No plugins or extensions required.
Can I use it offline?
After initial load, most features work offline. The core logic runs entirely in your browser with no network dependency.
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