Learn about how to use the new accounting capability for the TACACS+ server profile. 
    If you use a Terminal Access Controller Access-Control System Plus (
TACACS+) server for user authorization and
                authentication, you can now 
log accounting information to fully make
                use of the authentication, authorization, and accounting (AAA) framework that is the
                basis for TACACS+. 
The TACACS+ Accounting feature allows you to use a TACACS+ server profile
                to record user behavior, such as when a user started using a specific service, the
                duration of use for the service, and when they stopped using the service. The
                TACACS+ Accounting feature helps to create logs and records of the initiation and
                termination of services, as well as any services in progress during the user’s
                session, that you can then use later if needed for auditing purposes. 
When you configure and enable an Accounting server profile, the TACACS+ server
                provides information to the firewall about the initiation, duration, and termination
                of services by users. The firewall also generates a log when the TACACS+ server
                successfully provides the accounting records to the server that you configure in the
                profile. If the firewall is unable to successfully send the accounting records to
                any of the servers in the profile, the firewall generates a critical severity alert
                to the system logs.  
By using your existing TACACS+ server, you can now configure it to provide even more
                information about the use of services by users on your network, giving you even more
                robust visibility into user activity on your network.