What is 802.1X and how does it secure network access?

IEEE 802.1X is a port-based network access control standard that authenticates devices before granting them network access. It involves three components: the supplicant, which is the device requesting access; the authenticator, which is the switch or wireless access point that controls the port; and the authentication server, typically a RADIUS server, that verifies credentials. When a device connects, the authenticator blocks all traffic except authentication messages until the RADIUS server validates the credentials. Upon successful authentication, the port is opened for normal traffic.