As shown in Figure 12-4, to obtain IP addresses, users should pass the HWTACACS authentication.
After the configurations are complete, a valid remote user, namely user001@userdomain should obtain an IP address from the NAS through PPP address negotiation. However, no addresses are configured on the corresponding interface of the NAS to deliver. In this case, the NAS assigns an IP address to the user according to the authorization address configurations on the HWTACACS server.
In this case, replacement method is used to quickly locate the fault.
If no problem occurs when the HWTACACS server is not used, it indicates that there are problems with the HWTACACS server. If the user can access the NAS through Telnet, the fault can be located quickly without checking each phase.
Experienced engineers are advised to use the replacement method to quickly locate faults.