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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 8 Configuring Switch-Based Authentication
Controlling Switch Access with TACACS+
To remove the specified TACACS+ server name or address, use the no tacacs-server host hostname
global configuration command. To remove a server group from the configuration list, use the no aaa
group server tacacs+ group-name global configuration command. To remove the IP address of a
TACACS+ server, use the no server ip-address server group subconfiguration command.
Configuring TACACS+ Login Authentication
To configure AAA authentication, you define a named list of authentication methods and then apply that
list to various interfaces. The method list defines the types of authentication to be performed and the
sequence in which they are performed; it must be applied to a specific interface before any of the defined
authentication methods are performed. The only exception is the default method list (which, by
coincidence, is named default). The default method list is automatically applied to all interfaces except
those that have a named method list explicitly defined. A defined method list overrides the default
method list.
A method list describes the sequence and authentication methods to be queried to authenticate a user.
You can designate one or more security protocols to be used for authentication, thus ensuring a backup
system for authentication in case the initial method fails. The software uses the first method listed to
authenticate users; if that method fails to respond, the software selects the next authentication method in
the method list. This process continues until there is successful communication with a listed
authentication method or until all defined methods are exhausted. If authentication fails at any point in
this cycle—meaning that the security server or local username database responds by denying the user
access—the authentication process stops, and no other authentication methods are attempted.
Beginning in privileged EXEC mode, follow these steps to configure login authentication:
Step 6 end Return to privileged EXEC mode.
Step 7 show tacacs Verify your entries.
Step 8 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 aaa new-model Enable AAA.