Which ports are commonly used for RADIUS authentication and accounting? (Choose two.)

RADIUS (Remote Authentication Dial-In User Service) primarily uses UDP for its communication. UDP port 1812 is the standard port for RADIUS authentication messages. This is where the access request and access challenge packets are sent. UDP port 1813 is the standard port for RADIUS accounting messages, which track session start, stop, and usage statistics. While some older or non-standard implementations might use UDP ports 1645 for accounting and 1646 for authentication, the IETF standards (RFC 2865 and RFC 2866) define 1812 and 1813 as the primary ports. TCP ports are incorrect because RADIUS operates over UDP, not TCP.