802.1X is an Ethernet LAN authentication protocol used to provide secure access to a computer network. It’s a standard defined by the Institute of Electrical and Electronics Engineers (IEEE) for port-based network access control. As such, its main purpose is to verify that a device attempting to connect to the network is actually what it claims to be. 802.1X is commonly used in enterprise networks to protect against unauthorized access, enforce security policies, and make sure that data transmitted over the network is secure.