RADIUS
Remote Authentication Dial-In User Service
A centralized AAA protocol for network access.
Remote Authentication Dial-In User Service centralizes authentication, authorization, and accounting for network access, commonly serving VPNs, wireless networks, and 802.1X port-based control. A network device acts as a client that relays user credentials to the RADIUS server for a consistent policy and logging. Compared with TACACS+, RADIUS combines authentication and authorization, encrypts only the password rather than the full payload, and traditionally uses UDP. Its vendor-neutral design makes it a widely interoperable choice across mixed network equipment.
Remote AAA over UDP that encrypts only the password and bundles authentication with authorization. Cross-platform. Pair it against TACACS+ on the exam.
Looking RADIUS up is step one. Getting tested on it is step two.
A free account opens all 4 Domain 1 objectives, 271 exam-style questions with a lesson and a lab on each, a placement check that skips what you already know, and a dated plan. No card.
Not affiliated with or endorsed by CompTIA.