RADIUS server for authentication listens on which port by default?

RADIUS server for authentication listens on which port by default?

• A. 443
• B. 1812
• C. 8080
• D. 1813

Answer: (B)

RADIUS is used for centralized authentication and assigns distinct UDP ports for different AAA functions. For authentication, the standard port is 1812, where Access-Request messages from a network access server reach the RADIUS server and the server replies with Access-Accept or Access-Reject. Port 1813 is reserved for accounting traffic, not authentication. The other ports mentioned, 443 and 8080, are common web-related ports and not the default RADIUS authentication port. So the default port for authentication is 1812.

RADIUS is used for centralized authentication and assigns distinct UDP ports for different AAA functions. For authentication, the standard port is 1812, where Access-Request messages from a network access server reach the RADIUS server and the server replies with Access-Accept or Access-Reject. Port 1813 is reserved for accounting traffic, not authentication. The other ports mentioned, 443 and 8080, are common web-related ports and not the default RADIUS authentication port. So the default port for authentication is 1812.