What does AAA stand for?
AAA stands for Authentication, Authorization, and Accounting. The framework for controlling access: prove who you are (authentication), decide what you may do (authorization), and record what you did (accounting). RADIUS and TACACS+ are classic AAA servers.
AAA names the three steps of controlled access. Authentication proves who is asking, for example with a password and a second factor. Authorization decides what that identity may do: which network, which commands, which files. Accounting records what was done and when, so that use can be audited and, where it applies, billed. On networks the three functions are usually provided by a central server that switches, wireless controllers and VPN gateways consult.
AAA in practice: an example
A network engineer signs in to a router. The router sends the credentials to the central AAA server, which confirms the identity, returns the permission level for that engineer and then logs every configuration command with a timestamp. When a change causes an outage, the accounting log shows who typed it.
What AAA is confused with
AAA vs RADIUS: what is the difference?
AAA is the model. RADIUS is one protocol that carries it between a network device and the server; TACACS+ is another. What RADIUS stands for
AAA vs IAM: what is the difference?
IAM is the wider discipline of managing identities and their rights across an organization. AAA describes what happens at the moment of access: check identity, apply rights, record activity. What IAM stands for
Which exams cover AAA?
AAA is on the official CompTIA acronym list for two of the four exams covered here.
- Security+ SY0-801: 1.1 (General Security Concepts).
- A+ 220-1201 and 220-1202: 220-1201 2.0 (Networking).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. After a successful sign-in, a user is refused access to the finance share. Which part of AAA made that decision?
- Authentication
- Authorization
- Accounting
- Auditing of the firewall
Show the answer
B. Authorization. The identity was already proven, so authentication succeeded. Deciding what a proven identity may reach is authorization.
2. An auditor asks which administrator changed a switch configuration last Tuesday. Which AAA function provides the answer?
- Accounting
- Authentication
- Authorization
- Address translation
Show the answer
A. Accounting. Accounting is the record of what each identity did and when. Authentication and authorization happen before the action and do not keep the history.
Sources: RFC 2904: AAA Authorization Framework; RFC 2865: Remote Authentication Dial In User Service (RADIUS); NIST glossary: authentication, authorization, and accounting. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.