Full form: Remote Authentication Dial-In User Service
Also known as: Remote Authentication Dial-In User Service
Quick Definition
An open-standard AAA protocol that uses UDP and encrypts only the password.
RADIUS is an open-standard AAA protocol that centralises authentication, authorisation, and accounting for network access. It uses UDP ports 1812 (authentication/authorisation) and 1813 (accounting). Only the password is encrypted in RADIUS packets; other attributes (username, accounting data) are sent in cleartext. RADIUS is widely used for Wi-Fi authentication (802.1X), VPN access, and ISP dial-up.
RADIUS combines authentication and authorisation in a single Accept or Reject response. TACACS+ separates them into independent processes. RADIUS uses UDP; TACACS+ uses TCP.
Authentication, Authorisation, and Accounting — the three-component framework for controlling network access.
A Cisco-developed AAA protocol that uses TCP and encrypts the entire authentication payload.
An IEEE standard for port-based authentication that requires credentials before granting network access.
RADIUS is an open-standard AAA protocol that centralises authentication, authorisation, and accounting for network access. It uses UDP ports 1812 (authentication/authorisation) and 1813 (accounting). Only the password is encrypted in RADIUS packets; other attributes (username, accounting data) are sent in cleartext. RADIUS is widely used for Wi-Fi authentication (802.1X), VPN access, and ISP dial-up.
RADIUS combines authentication and authorisation in a single Accept or Reject response. TACACS+ separates them into independent processes. RADIUS uses UDP; TACACS+ uses TCP.
RADIUS falls under the Security domain of the 200-301 exam. Understanding it in context with related terms like tacacs-plus and aaa is essential for answering scenario-based questions correctly.