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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 TACACS+
The goal of TACACS+ is to provide a method for managing multiple network acc ess points from a single
management service. Your switch can be a network access server along with other Cisco rou ter s and
access servers. A network access server provides connections to a sing le user, to a netw or k or
subnetwork, and to interconnected networks as shown in Figure 6-1.
Figure6-1 Typical TACACS+ Network Configuration
TACACS+, administered through the AAA security services, can provide these services:
•Authentication—Provides complete control of authentication through login and password dialog,
challenge and response, and messaging support.
The authentication facility can conduct a dialog with the user (for example, after a username and
password are provided, to challenge a user with several questions, such as ho me add re ss, m othe r ’s
maiden name, service type, and social security number). The TACACS+ authentication service can
also send messages to user screens. For example, a message could notify users that their passwords
must be changed because of the company’s password aging policy.
•Authorization—Provides fine-grained control over user capabilities for the duration of the user’s
session, including but not limited to setting autocommands, access control, session duration, or
protocol support. You can also enforce restrictions on what commands a user can execute with the
TACACS+ authorization feature.
•Accounting—Collects and sends information used for billing, auditing, and reporting to the
TACACS+ daemon. Network managers can use the accounting facility to track user activity for a
security audit or to provide information for user billing. Accounting records include user identities,
start and stop times, executed commands (such as PPP), number of packets, and number of bytes.
The TACACS+ protocol provides authentication between the switch and the TACACS+ daemon, and it
ensures confidentiality because all protocol exchanges between the switch and the TACACS+ daemon
are encrypted.
UNIX workstation
(TACACS+
server 2)
UNIX workstation
(TACACS+
server 1)
Catalyst 3550
switches
Configure the switches with the
TACACS+ server addresses.
Set an authentication key
(also configure the same key on
the TACACS+ servers).
Enable AAA.
Create a login authentication method list.
Apply the list to the terminal lines.
Create an authorization and accounting
method list as required.
Catalyst 6500
series switch
Workstations
171.20.10.8
171.20.10.7
43270
Workstations