AAA
Authentication, Authorization, and Accounting
The framework for controlling access: prove who you are, decide what you can do, and record what you did.
AAA bundles three sequential control points: authentication confirms who a subject is, authorization decides what that subject may do, and accounting records what was done for billing, auditing, and forensics. It is the conceptual backbone behind protocols such as RADIUS and TACACS+, which centralize these decisions for network devices and remote access. On the exam, distinguish authentication, proving identity, from authorization, granting rights, since conflating the two is a common trap, and note that accounting is the piece that supports nonrepudiation.
Three As in order: Authentication (who are you?), Authorization (what may you do?), Accounting (what did you do?).
Looking AAA 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.
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