L31
Authentication, authorization, accounting and factors
Cram this first — memory hook
Who are you? What may you do? What did you do? Remote Authentication Dial-In User Service 1812 checks in; 1813 records the visit.
Exam trap
In this context Network Attached Storage is Network Access Server, not Network Attached Storage.
The slide facts
Identity is checked before appropriate access is granted. Local authentication uses local accounts; remote authentication uses centralized services. The factor slides emphasize know/have/are and additional contextual signals.
If you have time — extra
Identification states who you claim to be; authentication provides evidence; authorization grants permitted actions; accounting records activity. Authentication, Authorization and Accounting () groups the latter three. Something you know includes a password, something you have includes a hardware token, and something you are includes a biometric. Location, time and behavior can inform contextual decisions; they are not automatically interchangeable with independent primary factors. An One-Time Password is a code format: its factor classification depends on how it is generated and protected. Local authentication can support emergency access but creates per-device account-management work. Central authentication improves consistency and revocation but requires an availability/recovery plan. Remote Authentication Dial-In User Service () commonly uses User Datagram Protocol 1812 for authentication/authorization and 1813 for accounting. Terminal Access Controller Access-Control System Plus (TACACS+) commonly uses Transmission Control Protocol 49, often for device administration.
Walkthrough
A user claims an identity, presents proof, the system validates it, applies role/policy permissions and records the session/actions. A successful sign-in does not guarantee access to every resource.