Which AAA server protocol is commonly used with 802.1x authentication?

Which AAA server protocol is commonly used with 802.1x authentication?

• A. LDAP
• B. RADIUS
• C. TACACS+
• D. Kerberos

Answer: (B)

In 802.1X, the authentication framework relies on a protocol between the network device acting as the authenticator and the authentication server to verify credentials for network access. The commonly used protocol is RADIUS because it is specifically designed for network access authentication and centralizes authentication, authorization, and accounting for users trying to reach the network. It supports carrying EAP messages, which are used by 802.1X to negotiate secure authentication methods (like EAP-TLS or PEAP) between the supplicant and the server, with the server handling the actual verification. LDAP is a directory service protocol and isn’t used as the transport for the 802.1X authentication flow itself. TACACS+ is more focused on device administration and operates over TCP, making it less suitable for user network access control. Kerberos is used for ticket-based authentication within domains and isn’t the standard method for 802.1X network access.

In 802.1X, the authentication framework relies on a protocol between the network device acting as the authenticator and the authentication server to verify credentials for network access. The commonly used protocol is RADIUS because it is specifically designed for network access authentication and centralizes authentication, authorization, and accounting for users trying to reach the network. It supports carrying EAP messages, which are used by 802.1X to negotiate secure authentication methods (like EAP-TLS or PEAP) between the supplicant and the server, with the server handling the actual verification.

LDAP is a directory service protocol and isn’t used as the transport for the 802.1X authentication flow itself. TACACS+ is more focused on device administration and operates over TCP, making it less suitable for user network access control. Kerberos is used for ticket-based authentication within domains and isn’t the standard method for 802.1X network access.