What role does the RADIUS server play in EAP-TLS authentication?

In EAP-TLS authentication, the RADIUS server plays a critical role in authenticating user credentials. Specifically, it is responsible for verifying the identity of users attempting to connect to the network by checking their credentials against a specified identity store, which could be a database or an external directory service such as Active Directory.

When a client device tries to connect, it communicates with the RADIUS server through the access point or switch. The RADIUS server processes the authentication request, validates the user's credentials (which in the case of EAP-TLS are certificates), and then sends an appropriate response back to the client or the networking device. If the credentials are verified successfully, the RADIUS server allows the connection and can also send back session-specific information such as authorization details and session keys.

The other options mention tasks that are outside the scope of what a RADIUS server does in the context of EAP-TLS authentication. For example, while session keys are relevant to establishing secure connections, the generation of session keys usually occurs during the authentication process itself and is not a primary function of the RADIUS server. Network address translation and establishing IP routing are networking functions unrelated to the authentication processes handled by RADIUS servers.