Guides
Learn.
What a MAC address is and how it works, plus how to load the data behind this site into the tools that already expect it.
Fundamentals
Fundamentals
What is a MAC address?
Every network interface, Wi-Fi, Ethernet, Bluetooth, has one. Here's what it is, in plain terms, before the deeper dive into how it's structured.
Read the guide →Fundamentals
How MAC addresses work
Forty-eight bits, six bytes, and two of those bits mean something you can read off directly. Here's how the whole address is put together.
Read the guide →Fundamentals
Find your MAC address
The menu names shift a little between OS versions; the command-line methods below don't, so they're the ones worth remembering.
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MAC vs. IP address
Both identify a device on a network. Neither does the other one's job, and mixing them up is the source of a lot of confused troubleshooting.
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MAC randomization
Your phone almost certainly isn't broadcasting its real MAC address anymore. Here's why that started, and how to tell the difference.
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History of the MAC address
The 48-bit format on every network interface today traces back to a lab at Xerox PARC in 1973, and it's been extended, not replaced, ever since.
Read the guide →Downloads & tools
Guide · Cisco ISE
Cisco ISE
ISE's profiler leans on the MAC vendor to fingerprint endpoints. When the Feed Service can't reach Cisco, or its cache just hasn't kept up with IEEE, here's how to load a current OUI file by hand.
Read the guide →Guide · Wireshark & tshark
Wireshark
The vendor name next to every MAC address in Wireshark's packet list comes from one text file, bundled at install time and never touched again until your next upgrade.
Read the guide →Guide · Nmap
Nmap
Every "MAC Address: ... (Vendor Name)" line nmap prints during a scan comes from nmap-mac-prefixes, a file that only updates when nmap itself does.
Read the guide →Guide · CSV
CSV
Six columns, one row per registered block, every OUI size IEEE assigns, not just the 24-bit ones. No account, no rate limit, just a file.
Read the guide →Guide · JSON
JSON
The same data as the CSV, as one JSON array, for anything that would rather Marshal than split on commas.
Read the guide →Guide · Self-hosted
Self-hosted
A single OUI file is a weekend project. A lookup engine that holds up under real production traffic, and stays correct as IEEE's data changes under it, is not.
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Looking for the raw data?
Every guide above links to the exact file it covers, or grab all five formats at once from the downloads page.