In RADIUS central authentication, which item is not one of the devices typically involved?

• A. The supplicant
• B. The verifier
• C. The authenticator
• D. The RADIUS central authentication server

Answer: (B)

In RADIUS central authentication, three roles participate: the supplicant (the user or device requesting access), the authenticator (the network device like a switch or wireless AP that enforces access and forwards credentials), and the central RADIUS server (the authentication server that checks credentials and returns allow or deny). There isn’t a separate device called a verifier in this model—the server itself performs the credential verification when it processes the Access-Request and responds accordingly. So the item described as the verifier isn’t a standard device involved in typical RADIUS architecture. The other roles clearly fit: the supplicant requests access, the authenticator forwards it to the server, and the central server performs the authentication.