What is what does oui mean?

OUI stands for “Organisation Unique Identifier” and is a 24-bit number assigned by the Institute of Electrical and Electronics Engineers (IEEE) to identify different vendors of networking equipment. The first 3 bytes of a MAC (Media Access Control) address represent the organization that manufactured the device, and these bytes are also called the OUI or MAC OUI. The OUI is used in identifying devices on a network and is often used as a way to blacklist suspicious devices.