Which protocol provides centralized authentication, authorization, and accounting for network access control?

Which protocol provides centralized authentication, authorization, and accounting for network access control?

• A. LDAP
• B. DNS
• C. HTTPS
• D. RADIUS

Answer: (D)

RADIUS provides centralized authentication, authorization, and accounting for network access control. It’s designed for network access scenarios where a client device like a wireless AP, VPN concentrator, or switch forwards a user’s credentials to a central server. The RADIUS server then authenticates the user, enforces policy-based authorization (determining what services or resources the user can access), and performs accounting by logging session start/stop, duration, and usage. This centralized AAA model simplifies enforcement and auditing across the network. LDAP, while a directory service that can store and verify user credentials, is not itself a complete AAA solution for network access control and typically lacks the built-in accounting component. DNS and HTTPS serve different functions (name resolution and secure web transport, respectively) and do not provide centralized AAA for network access.

RADIUS provides centralized authentication, authorization, and accounting for network access control. It’s designed for network access scenarios where a client device like a wireless AP, VPN concentrator, or switch forwards a user’s credentials to a central server. The RADIUS server then authenticates the user, enforces policy-based authorization (determining what services or resources the user can access), and performs accounting by logging session start/stop, duration, and usage. This centralized AAA model simplifies enforcement and auditing across the network.

LDAP, while a directory service that can store and verify user credentials, is not itself a complete AAA solution for network access control and typically lacks the built-in accounting component. DNS and HTTPS serve different functions (name resolution and secure web transport, respectively) and do not provide centralized AAA for network access.