CCNA Practice Exam 2026 – Complete Study Resource

The command to enable AAA (Authentication, Authorization, and Accounting) security on a Cisco router is "aaa new-model." This command activates the AAA framework on the device, allowing you to configure authentication methods, set up authorization for various commands, and collect accounting data.

Once you have entered this command in global configuration mode, you can then define specific AAA users, authentication methods, and authorization policies that will govern access to the router.

The other options do not accurately reflect valid commands used in Cisco IOS. For instance, the first option is not a recognized command in Cisco IOS, while the third option suggests an incorrect command format that wouldn't function for enabling AAA. The last option also does not match a valid command syntax for enabling AAA.