How Do You Generate a Random MAC Address and Look Up Its Vendor?
Updated 2026-06-27
To generate a random MAC address and look up its vendor, use the in-browser MAC Address Generator & Lookup: press Generate for safe locally-administered unicast addresses, or paste any MAC to decode its vendor (OUI) and flags. Nothing is uploaded - it all runs on your device.
Generate safe test MAC addresses
Real network gear ships with a universally-administered address burned in by the manufacturer. If you need MACs for a lab, a virtual machine, mock data, or automated tests, you want addresses that cannot collide with real hardware. That is exactly what this tool produces.
Every generated address is a locally-administered unicast MAC. Behind the scenes it sets the locally-administered bit and clears the multicast bit in the first octet, and it draws randomness from your browser's Web Crypto API rather than weak pseudo-randomness.
To build a batch:
- Pick a Notation: Colon, Hyphen, Dot (Cisco aabb.ccdd.eeff), or Bare.
- Set Count anywhere from 1 to 50.
- Optionally flip on Uppercase.
- Press Generate, then Copy all.
Press Generate again to re-roll a fresh set instantly.
Look up the vendor and decode any MAC
Paste a MAC into the Lookup & inspect box and the tool normalizes it and decodes it. Input is case-insensitive and accepts colon, hyphen, dot, or bare notation, so you can drop in whatever your switch logs or device label gave you.
You get back three things:
- Vendor (OUI) - the manufacturer behind the first three bytes, drawn from a curated list of common prefixes (Apple, Google, Cisco, Intel, Dell, Samsung, VMware, VirtualBox, QEMU/KVM, Hyper-V, Raspberry Pi and more). Uncommon prefixes show as Unknown because the full IEEE registry is too large to bundle.
- Cast - Unicast or Multicast, from bit 0 of the first octet.
- Administration - Universal (OUI) or Locally administered, from bit 1 of the first octet.
Those two flags live in the low two bits of the first octet: bit 0 is unicast/multicast, bit 1 is universal/local. That is why a randomly generated MAC reads as Locally administered while a real Apple device reads as Universal.
Convert a MAC between formats
The same lookup view doubles as a format converter. Paste one MAC and the MAC Address Generator & Lookup shows it in all four notations at once - colon, hyphen, Cisco dot, and bare - each with its own copy button. So if your firewall wants colon-separated but your Cisco config wants dotted groups, copy the row you need and move on.
Why local-only matters
MAC addresses identify physical interfaces, and pasting them into a random web form is a small privacy leak. Here there is no leak to worry about:
- Generation uses your browser's crypto randomness, no server round-trip.
- The vendor list ships with the page, so lookups never call out.
- Nothing you type or generate leaves your device.
That makes it equally safe for production gear, customer hardware, or anything under NDA.
Pair it with IP tools
MAC addresses sit at layer 2; the moment you are debugging connectivity you are also juggling IP addresses. When you need to expand an IPv6 address or flip an IPv4 between decimal, hex, and binary, reach for the IP Address Converter - same privacy-first, in-browser approach. Together they cover the addressing layer of most network-troubleshooting sessions without sending a single packet of your data anywhere.