In which phase does the RADIUS server authenticate user credentials in EAP-FAST?

In EAP-FAST (Flexible Authentication via Secure Tunneling), the RADIUS server authenticates user credentials during Phase 2. This phase is critical as it follows the establishment of a secure tunnel in Phase 1. During Phase 2, the actual user credentials are transmitted securely through this tunnel for authentication against the RADIUS server.

Phase 0 involves the tunneling establishment process, and Phase 1 is primarily focused on establishing a secure tunnel, ensuring that subsequent transmissions can occur securely. Phase 3 involves the completion of the authentication process and the establishment of a session, but the verification of the user credentials specifically happens in Phase 2, making it the correct answer. Understanding these phases is essential for grasping how EAP-FAST manages secure authentication.