Cisco IOS supports three versions of TACACS—TACACS, extended TACACS, and TACACS+. All three methods authenticate users and deny access to users who do not have a valid username/password pairing.
Cisco has also developed Cisco Secure Access Control Server (CSACS), a flexible family of security servers that supports both RADIUS and TACACS+. You can even run debugging commands on the Cisco Secure ACS software. In UNIX, you can modify files, such as syslog.conf and csu.cfg, to change the output to your screen. For more details on how to debug on a UNIX server, see www.cisco.com/warp/public/480/cssample2x.html#debug.
TACACS+ has the following features:
TCP packets (port 49) ensure that ...