正解:C
802.1X is a port-based Network Access Control (NAC) method that enforces authentication before allowing access to the network. It uses a RADIUS server for identity verification and policy enforcement, ensuring only authorized users/devices gain access.
* A. Standard ACL filters traffic by IP, not identity.
* B. MAC filtering controls devices by hardware address but can be spoofed.
* D. SSO (Single Sign-On) provides user convenience across services, not network-level access control.
References (CompTIA Network+ N10-009):
* Domain: Network Security - NAC, 802.1X authentication, identity-based access.