Understanding Radius - Cisco Catalyst 3560-X Software Configuration Manual

Controlling Switch Access with RADIUS
For complete syntax and usage information for the commands used in this section, see the Cisco IOS
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Security Command Reference, Release 12.4 and the
These sections contain this configuration information:
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Understanding RADIUS

RADIUS is a distributed client/server system that secures networks against unauthorized access.
RADIUS clients run on supported Cisco routers and switches. Clients send authentication requests to a
central RADIUS server, which contains all user authentication and network service access information.
The RADIUS host is normally a multiuser system running RADIUS server software from Cisco (Cisco
Secure Access Control Server Version 3.0), Livingston, Merit, Microsoft, or another software provider.
For more information, see the RADIUS server documentation.
We recommend a redundant connection between a switch stack and the RADIUS server. This is to help
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ensure that the RADIUS server remains accessible in case one of the connected stack members is
removed from the switch stack.
Use RADIUS in these network environments that require access security:
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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
1-18
Understanding RADIUS, page 1-18
RADIUS Operation, page 1-19
RADIUS Change of Authorization, page 1-20
Configuring RADIUS, page 1-26
Displaying the RADIUS Configuration, page 1-39
Networks with multiple-vendor access servers, each supporting RADIUS. For example, access
servers from several vendors use a single RADIUS server-based security database. In an IP-based
network with multiple vendors' access servers, dial-in users are authenticated through a RADIUS
server that has been customized to work with the Kerberos security system.
Turnkey network security environments in which applications support the RADIUS protocol, such
as in an access environment that uses a smart card access control system. In one case, RADIUS has
been used with Enigma's security cards to validates users and to grant access to network resources.
Networks already using RADIUS. You can add a Cisco switch containing a RADIUS client to the
network. This might be the first step when you make a transition to a TACACS+ server. See
Figure 1-2 on page 1-19.
Network in which the user must only access a single service. Using RADIUS, you can control user
access to a single host, to a single utility such as Telnet, or to the network through a protocol such
as IEEE 802.1x. For more information about this protocol, see
Port-Based Authentication."
Networks that require resource accounting. You can use RADIUS accounting independently of
RADIUS authentication or authorization. The RADIUS accounting functions allow data to be sent
at the start and end of services, showing the amount of resources (such as time, packets, bytes, and
so forth) used during the session. An Internet service provider might use a freeware-based version
of RADIUS access control and accounting software to meet special security and billing needs.
Chapter 1 Configuring Switch-Based Authentication
Cisco IOS IPv6 Command
Chapter 1, "Configuring IEEE 802.1x
Reference.
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