Cisco Systems 3550 RADIUS Operation, Configuring RADIUS

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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter6 Administering the Swi tc h Controlling Switch Access with RADIUS
Figure6-2 Typical AAA Network Configuration
RADIUS Operation
When a user attempts to log in and authenticate to a switch that is access controlled by a RADIUS server,
these events occur:
1. The user is prompted to enter a username and password.
2. The username and encrypted password are sent over the netwo rk to th e RAD IUS serv er.
3. The user receives one of these responses from the RADIUS server:
a. ACCEPT—The user is authenticated.
b. REJECT—The user is either not authenticated and is prompted to re-enter the username and
password, or access is denied.
c. CHALLENGE—A challenge requires additional data from the user.
d. CHALLENGE PASSWORD—A response requests the user to select a new password.
The ACCEPT or REJECT response is bundled with additional data that is used for privileged EXEC or
network authorization. Users must first successfully complete RADIUS authentication before
proceeding to RADIUS authorization, if it is enabled. The additional data included with the ACCEPT or
REJECT packets includes these items:
•Telnet, rlogin, or privileged EXEC services
•Connection parameters, including the host or client IP address , ac ce ss l ist, a nd user ti meouts
Configuring RADIUS
This section describes how to configure your switch to support RA DIU S. A t a m inimu m, you m ust
identify the host or hosts that run the RADIUS server software and define the method lists for RADIUS
authentication. You can optionally define method lists for RADIUS authorization and accounting.
A method list defines the sequence and methods to be used to authenticate, to authorize, or to keep
accounts on a user. You can use method lists to designate one or more security protocols to be used (such
as TACACS+ or local username lookup), thus ensuring a backup system if the initial method fails. The
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RADIUS
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TACACS+
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TACACS+
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R1
R2
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Catalyst 3550 switch
Remote
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Workstation