The JUNOS Software supports three methods of user authentication: local password authentication, Remote Authentication Dial-In User Service (RADIUS), and Terminal Access Controller Access Control System Plus (TACACS+).
With local password authentication, you configure a password for each user allowed to log in to the router.
RADIUS and TACACS+ are authentication methods for validating users who attempt to access the router using telnet. They are both distributed client-server systems—the RADIUS and TACACS+ clients run on the router, and the server runs on a remote network system.
You can configure the router to be both a RADIUS and TACACS+ client, and you can also configure authentication passwords in the JUNOS configuration file. You can prioritize the methods to configure the order in which the software tries the different authentication methods when verifying user access.