| 11.4 |  | PPPoE and the PIX Security Appliance |
| 11.4.4 |  | Monitoring and troubleshooting the PPPoE client |

| Once the PIX Security Appliance has been configured to support PPPoE, it is important that administrators are able to monitor and troubleshoot the technology. There are several commands that are useful in doing this. These include several show and debug commands, which are examined in this section and in the corresponding command references.

show commands
There are a number of show commands, which can be used to gain information about a PPPoE implementation involving a PIX Security Appliance. The show vpdn command displays PPPoE tunnel and session information. To view only session information, use the show vpdn session command. To view only tunnel information, use the show vpdn tunnel command.

Figure shows the kind of information provided by the show vpdn commands.

Another available command is show vpdn pppinterface, which can be used to view the address of the Access Concentrator (AC) once a PPPoE session has been established. When the PIX Security Appliance is unable to find an AC, the address of the AC is displayed as 0.0.0.0.

To view local usernames, use the show vpdn username command. To view the configured VPDN groups, use the show vpdn group command. When a PPPoE session is established, use the show ip address outside pppoe command to view the IP address assigned by the PPPoE server.

For further information regarding these commands and their syntaxes, see the Command Reference guide.

debug commands
When PPPoE is being implemented, there is one primary PPPoE debug command that administrators should be familiar with. This is the debug pppoe command. For the purposes of troubleshooting the PPPoE client, the debug pppoe command gives the administrator the ability to get pertinent information related to PPPoE events, errors, and packets.

For further information regarding the debug pppoe command and its arguments, see the Command Reference guide.