What is RADIUS in Security+?
D1 · General · CompTIA Security+ SY0-701RADIUS (Remote Authentication Dial-In User Service) is a client/server protocol that provides centralized AAA (Authentication, Authorization, and Accounting) services for network access control — dial-up, VPN, Wi-Fi, and network device access.
RADIUS flow: User → NAS (Network Access Server) → RADIUS server → authenticates against directory (AD/LDAP) → sends Access-Accept or Access-Reject.
Ports: 1812 (authentication), 1813 (accounting). Legacy: 1645/1646.
RADIUS flow: User → NAS (Network Access Server) → RADIUS server → authenticates against directory (AD/LDAP) → sends Access-Accept or Access-Reject.
Ports: 1812 (authentication), 1813 (accounting). Legacy: 1645/1646.
RADIUS is the standard for 802.1X network authentication (wired and Wi-Fi). Enterprise Wi-Fi uses WPA2/3-Enterprise + RADIUS. TACACS+ is Cisco's alternative (encrypts entire payload vs. RADIUS which only encrypts password). Know RADIUS ports (1812/1813) for the exam.