CCIE Security Exam Quick Reference Sheets

Chapter 2. Security Protocols

RADIUS

• RADIUS is a client/server protocol that uses the User Datagram Protocol (UDP) as the transport protocol. It is used for authentication, authorization, and accounting (AAA).
• The RADIUS specification RFC 2865 obsoletes RFC 2138. The RADIUS accounting standard RFC 2866 obsoletes RFC 2139.
• The RADIUS protocol defines things in terms of attributes. Each attribute may take on one of a set of values. When a RADIUS packet is exchanged among clients and servers, one or more attributes and values are sent pairwise as an attribute-value pair (A-V pair).

Figure 2-1 depicts the RADIUS authentication process.

FIGURE 2-1 RADIUS authentication process

Step 1. Network Access Server Sends an Access Request to AAA server. ...