Which statement best describes 802.1X?

• A. 802.1X is a wireless encryption standard.
• B. 802.1X is a DNS protocol.
• C. 802.1X is a port-based network access control protocol used to authenticate devices before granting network access.
• D. 802.1X is a VPN protocol.

Answer: (C)

802.1X is a port-based network access control protocol that authenticates devices before they’re allowed onto the network. It works by requiring a device to prove its identity before the switch or wireless access point (the authenticator) grants access. The device trying to connect is the supplicant, and an authentication server (typically RADIUS) verifies the credentials. When a device first connects, its port is placed in an unauthenticated state and traffic is blocked. The supplicant and the authentication server exchange credentials using EAP messages, often over EAPOL, and once authentication succeeds, the port switches to an authorized state and normal network access is allowed. This mechanism applies to both wired and wireless networks, providing a centralized way to control who can connect.

It’s not a wireless encryption standard (encryption schemes for Wi-Fi like WPA2/WPA3), not a DNS protocol, and not a VPN protocol.