1-9Figure 1-6 Basic message exchange process of HWTACACS for a Telnet userHost HWTACACS client HWTACACS server1) The user logs in2) Start-authentication packet3) Authentication response requesting the username4) Request for username5) The user inputs the username6) Authentication continuance packet with theusername7) Authentication response requesting the loginpassword8) Request for password9) The user inputs the password11) Authentication response indicating successfulauthentication12) User authorization request packet13) Authorization response indicating successfulauthorization14) The user logs in successfully15) Start-accounting request16) Accounting response indicating the start ofaccounting17) The user logs off18) Stop-accounting request19) Stop-accounting response10) Authentication continuance packet with thelogin password2) A Telnet user sends an access request to the NAS.3) Upon receiving the request, the HWTACACS client sends a start-authentication packet to theHWTACACS server.4) The HWTACACS server sends back an authentication response requesting the username.5) Upon receiving the response, the HWTACACS client asks the user for the username.6) The user inputs the username.7) After receiving the username from the user, the HWTACACS client sends to the server acontinue-authentication packet carrying the username.8) The HWTACACS server sends back an authentication response, requesting the login password.9) Upon receipt of the response, the HWTACACS client asks the user for the login password.10) The user inputs the password.11) After receiving the login password, the HWTACACS client sends to the HWTACACS server acontinue-authentication packet carrying the login password.12) The HWTACACS server sends back an authentication response indicating that the user haspassed authentication.
