Administrator Guide

Monitoring TACACS+
To view information on TACACS+ transactions, use the following command.
• View TACACS+ transactions to troubleshoot problems.
EXEC Privilege mode
debug tacacs+
TACACS+ Remote Authentication
The system takes the access class from the TACACS+ server. Access class is the class of service that restricts Telnet access and packet
sizes.
If you have congured remote authorization, the system ignores the access class you have congured for the VTY line and gets this access
class information from the TACACS+ server. The system must know the username and password of the incoming user before it can fetch
the access class from the server. A user, therefore, at least sees the login prompt. If the access class denies the connection, the system
closes the Telnet session immediately. The following example demonstrates how to congure the access-class from a TACACS+ server.
This conguration ignores the congured access-class on the VTY line. If you have congured a deny10 ACL on the TACACS+ server, the
system downloads it and applies it. If the user is found to be coming from the 10.0.0.0 subnet, the system also immediately closes the Telnet
connection. Note, that no matter where the user is coming from, they see the login prompt.
When conguring a TACACS+ server host, you can set dierent communication parameters, such as the key password.
Example of Specifying a TACACS+ Server Host
Dell(conf)#
Dell(conf)#aaa authentication login tacacsmethod tacacs+
Dell(conf)#aaa authentication exec tacacsauthorization tacacs+
Dell(conf)#tacacs-server host 25.1.1.2 key Force
Dell(conf)#
Dell(conf)#line vty 0 9
Dell(config-line-vty)#login authentication tacacsmethod
Dell(config-line-vty)#end
Specifying a TACACS+ Server Host
To specify a TACACS+ server host and congure its communication parameters, use the following command.
• Enter the host name or IP address of the TACACS+ server host.
CONFIGURATION mode
tacacs-server host {hostname | ip-address} [port port-number] [timeout seconds] [key key]
Congure the optional communication parameters for the specic host:
• port port-number: the range is from 0 to 65535. Enter a TCP port number. The default is 49.
• timeout seconds: the range is from 0 to 1000. Default is 10 seconds.
• key key: enter a string for the key. The key can be up to 42 characters long. This key must match a key congured on the
TACACS+ server host. This parameter must be the last parameter you congure.
If you do not congure these optional parameters, the default global values are applied.
Example of Connecting with a TACACS+ Server Host
To specify multiple TACACS+ server hosts, congure the tacacs-server host command multiple times. If you congure multiple
TACACS+ server hosts, Dell Networking OS attempts to connect with them in the order in which they were congured.
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