Radius - HP 10500 Series Configuration Manual

RADIUS

Remote Authentication Dial-In User Service (RADIUS) is a distributed information interaction protocol that
uses a client/server model. It can protect networks against unauthorized access and is often used in
network environments that require both high security and remote user access.
RADIUS uses UDP port 1812 for authentication and UDP port 1813 for accounting.
RADIUS was originally designed for dial-in user access. With the addition of new access methods,
RADIUS has been extended to support additional access methods, including Ethernet and ADSL.
RADIUS provides access authentication, authorization, and accounting services. The accounting function
collects and records network resource usage information.
Client/server model
The RADIUS client runs on every NAS on the network to pass user information to the RADIUS server and
determines to reject or accept each access request based on the server response.
The RADIUS server runs on the computer or workstation at the network center and maintains information
related to user authentication and network access. It receives connection requests, authenticates users,
and returns access control information (for example, rejecting or accepting the user access request) to the
client.
The RADIUS server typically maintains the following databases: Users, Clients, and Dictionary.
See Figure 2.
Figure 2 RADIUS server databases
Users
Users—Stores user information, such as the usernames, passwords, applied protocols, and IP
•
addresses.
• Clients—Stores information about RADIUS clients, such as shared keys and IP addresses.
Dictionary—Stores RADIUS protocol attributes and their values.
•
Security and authentication mechanisms
The RADIUS client and the RADIUS server use a shared key to authenticate RADIUS packets and encrypt
user passwords exchanged between them. For security, this key must be manually configured on the
client and the server.
RADIUS servers support multiple authentication protocols, including PAP and CHAP of PPP. A RADIUS
server can also act as the client of another AAA server to provide authentication proxy services.
Basic RADIUS message exchange process
Figure 3 illustrates the interactions between the host, the RADIUS client, and the RADIUS server.
RADIUS servers
Clients Dictionary
2