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Cisco 10000 Series Router Software Configuration Guide
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Chapter 5 Configuring the Layer 2 Tunnel Protocol Access Concentrator and Network Server
L2TP Network Server
Caution
Because debugging output is assigned high priority in the CPU process, it can render the system
unusable. For this reason, use debug commands only to troubleshoot specific problems or during
troubleshooting sessions with Cisco Systems technical support personnel. Moreover, it is best to use
debug commands during periods of lower network traffic and fewer users. Debugging during these
periods decreases the likelihood that increased debug command processing overhead will affect system
use.
Router#
show vpdn tunnel
Displays information about all active L2TP tunnels in a VPDN.
Router#
show vpdn tunnel all
Displays information about all active L2TP tunnels.
Router#
debug aaa accounting
Displays information on accountable events as they occur.
Router#
debug aaa authorization
Displays information on AAA authorization.
Router#
debug ppp chap
Displays authentication protocol messages for Challenge
Authentication Protocol (CHAP) packet exchanges.
This command is useful when a CHAP authentication failure
occurs due to a configuration mismatch between devices.
Verifying and correcting any username and password mismatch
resolves the problem.
Router#
debug ppp negotiation
Displays information on traffic and exchanges in an internetwork
implementing PPP.
Router#
debug ppp negotiation chap
Used to decipher a CHAP negotiation problem due to a
connectivity problem between a Cisco and non-Cisco device.
Router#
debug radius
Displays information associated with RADIUS.
Router#
debug vpdn events
Displays L2TP errors and events that are a part of normal tunnel
establishment or shutdown for VPNs.
Router#
debug vpdn errors
Displays errors that prevent a tunnel from being established or
errors that cause an established tunnel to be closed.
Command
Purpose
