Explanation: 802.1X is an authentication component that must be used in a network access control (NAC) solution. NAC is a method of enforcing security policies on devices that want to access a network, by verifying their identity, compliance, and authorization. 802.1X is a standard that defines how to provide authentication for devices trying to connect to a LAN or WLAN. It uses the Extensible Authentication Protocol (EAP) to exchange authentication information between the device (supplicant), the network access device (authenticator), and the authentication server (typically RADIUS or TACACS+). 802.1X can prevent unauthorized devices from accessing the network, and can also assign them to different VLANs or apply different policies based on their role or group.
IPSec is a protocol suite that provides encryption, authentication, and integrity for IP packets. It can be used to create secure VPN tunnels between networks or hosts. IPSec is not an authentication component for NAC, but rather a security component for protecting data in transit.
EAP is a framework that supports multiple authentication methods, such as passwords, certificates, tokens, or biometrics. EAP is used by 802.1X to provide authentication for network access, but it is not a component by itself. EAP requires a carrier protocol, such as 802.1X, to transport the authentication messages.
TACACS+ is a protocol that provides authentication, authorization, and accounting (AAA) services for network devices or users. It can be used as an authentication server for 802.1X, but it is not an authentication component for NAC by itself. TACACS+ requires a client-server protocol, such as 802.1X, to communicate with the network access device.
ReferencesWhat is 802.1X Network Access Control (NAC)?Compare TACACS + and RADIUS802.1X: What EXACTLY is it regarding WPA and EAP?CompTIA Network+ Certification All-in-One Exam Guide, Eighth Edition (Exam N10-008)