Which protocol is used to manage credentials centrally, combining authentication and authorization?

Which protocol is used to manage credentials centrally, combining authentication and authorization?

• A. DNS
• B. FTP
• C. SNMP
• D. RADIUS

Answer: (D)

Centralized authentication and authorization are handled by a protocol that implements AAA—authentication, authorization, and accounting—so that a single server enforces who can access the network and what they can do. RADIUS does this by collecting user credentials from network access devices (like switches, wireless controllers, or VPN gateways), validating them against its database or an external directory, and returning an access decision along with attributes that define the user's allowed services, VLAN assignment, or session limits. This approach keeps credentials and access policies consistent across the entire network, rather than embedding policies on each device. DNS translates domain names to IP addresses, not credentials or access decisions. FTP is a file transfer protocol unrelated to centralized access control. SNMP is used for monitoring and managing devices, not for central authentication and authorization. RADIUS is the standard choice for combining authentication and authorization in a centralized way across network resources.

Centralized authentication and authorization are handled by a protocol that implements AAA—authentication, authorization, and accounting—so that a single server enforces who can access the network and what they can do. RADIUS does this by collecting user credentials from network access devices (like switches, wireless controllers, or VPN gateways), validating them against its database or an external directory, and returning an access decision along with attributes that define the user's allowed services, VLAN assignment, or session limits. This approach keeps credentials and access policies consistent across the entire network, rather than embedding policies on each device.

DNS translates domain names to IP addresses, not credentials or access decisions. FTP is a file transfer protocol unrelated to centralized access control. SNMP is used for monitoring and managing devices, not for central authentication and authorization. RADIUS is the standard choice for combining authentication and authorization in a centralized way across network resources.