The authenticator is the ________.

• A. Workgroup switch
• B. Central authentication server
• C. Client
• D. None of the above

Answer: (A)

In 802.1X network access control, the authenticator is the device that sits between the client and the authentication server and enforces access decisions. On a wired LAN, this role is typically a workgroup switch—the switch the client plugs into. It blocks traffic on the port until the client completes authentication, then allows traffic to flow. The central authentication server, such as a RADIUS server, performs credential verification and policy decisions, but isn’t the device enforcing access at the edge. The client is the device seeking access (the supplicant). So, the authenticator being the workgroup switch fits the typical wired-network scenario where a switch gates access until authentication succeeds.