MAC Address Lookup

What this checks

• Normalization of the entered MAC address or prefix into uppercase hexadecimal without separators.
• Longest-prefix vendor matching across committed 24-bit, 28-bit, and 36-bit IEEE-style assignment records.
• Locally administered and multicast flags derived from the first octet of the normalized input.

How to interpret results

• A vendor match means the normalized prefix exists in the committed OUI table for this release.
• No vendor match means the input normalized successfully but no committed prefix matched it.
• Locally administered or multicast flags describe address semantics and do not by themselves identify a device type.

Common issues

• Locally administered, randomized, or virtualized MAC addresses may not identify the original hardware vendor reliably.
• Prefix-only input can reveal the assigned vendor block, but not a specific device instance.

Privacy note

This lookup runs on the site's server with a committed vendor-prefix table and does not call a third-party MAC vendor API.

Frequently Asked Questions

What is an OUI or vendor prefix?

An OUI-style prefix is the vendor-assigned portion of a MAC address. This tool matches 24-bit, 28-bit, and 36-bit IEEE-style assignments.

Can a locally administered MAC still map to a vendor?

Yes, but a locally administered bit means the address may have been rewritten or generated locally even if the prefix matches a vendor assignment.