MAC Address Generator

Network Client-side mac address generator random oui network

This tool runs entirely client-side, in your browser: your data is never sent anywhere.

What it does

Generates one or more random MAC addresses. You can optionally provide an OUI prefix (the first 3 bytes, e.g. 00:1A:2B) to keep a specific vendor identity, and choose whether the generated address should be "locally administered" (a bit flag that marks a MAC as manually assigned rather than burned-in by a manufacturer).

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How it works

If you provide an OUI prefix, its 3 bytes are kept fixed; otherwise all 6 bytes are random.
The remaining bytes are filled with cryptographically random values using crypto.getRandomValues.
The first byte's bits can optionally be adjusted:

Locally administered bit (2nd least-significant bit of the first byte) is set to 1 when the checkbox is checked, marking the address as manually assigned instead of vendor-assigned.
The multicast bit (least-significant bit) is always cleared so the generated address looks like a normal unicast MAC.

This is handy for lab environments, testing OUI-based MAC lookups (see the MAC OUI Resolver), or generating placeholder device identifiers. Nothing is sent anywhere — everything happens in your browser.