Monitoring TACACS+To view information on TACACS+ transactions, use the following command.• View TACACS+ transactions to troubleshoot problems.EXEC Privilege modedebug tacacs+TACACS+ Remote AuthenticationThe system takes the access class from the TACACS+ server. Access class is the class of service that restricts Telnet access and packetsizes.If you have configured remote authorization, the system ignores the access class you have configured for the VTY line and gets this accessclass information from the TACACS+ server. The system must know the username and password of the incoming user before it can fetchthe access class from the server. A user, therefore, at least sees the login prompt. If the access class denies the connection, the systemcloses the Telnet session immediately. The following example demonstrates how to configure the access-class from a TACACS+ server.This configuration ignores the configured access-class on the VTY line. If you have configured a deny10 ACL on the TACACS+ server, thesystem 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 Telnetconnection. Note, that no matter where the user is coming from, they see the login prompt.When configuring a TACACS+ server host, you can set different communication parameters, such as the key password.Example of Specifying a TACACS+ Server HostDell(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 ForceDell(conf)#Dell(conf)#line vty 0 9Dell(config-line-vty)#login authentication tacacsmethodDell(config-line-vty)#endSpecifying a TACACS+ Server HostTo specify a TACACS+ server host and configure its communication parameters, use the following command.• Enter the host name or IP address of the TACACS+ server host.CONFIGURATION modetacacs-server host {hostname | ip-address} [port port-number] [timeout seconds] [key key]Configure the optional communication parameters for the specific 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 configured on theTACACS+ server host. This parameter must be the last parameter you configure.If you do not configure these optional parameters, the default global values are applied.Example of Connecting with a TACACS+ Server HostTo specify multiple TACACS+ server hosts, configure the tacacs-server host command multiple times. If you configure multipleTACACS+ server hosts, Dell Networking OS attempts to connect with them in the order in which they were configured.Security 771
