Cisco Certified Network Professional 2026 – 400 Free Practice Questions to Pass the Exam

RADIUS (Remote Authentication Dial-In User Service) is designed as a dual-purpose protocol, proficiently managing both authentication and authorization tasks. When a user attempts to access a network, RADIUS authenticates the credentials they present and subsequently determines whether to grant or deny access based on user permissions and profiles.

RADIUS works primarily over UDP and generally employs a centralized server model, allowing for efficient management of multiple users from a single location. This centralization is particularly advantageous in environments where network access needs to be controlled consistently across many devices or services.

On the other hand, TACACS+ (Terminal Access Controller Access-Control System Plus) provides similar capabilities but typically manages authentication, authorization, and accounting distinctly; it separates these functions, making it more geared toward comprehensive access management rather than acting as a dual-purpose solution.

Local authentication involves managing credentials directly on the device itself. While it handles authentication, it does not typically extend to authorization decisions at a more granular policy level beyond what is defined on that local device.

Line authentication is specific to controlling access depending on line vty or console settings on routers and switches. While it may provide basic authentication mechanisms, it lacks the centralized management and dual-purpose nature intrinsic to RADIUS.

Thus, RADIUS stands out as the