As shown in the following figure, the AR functions as the enterprise egress router, and the branch and headquarters establish an L2TP tunnel. Users on outbound interface GE1/0/0 connect to the network through PPPoE dialup.
The private network user (PC1) can successfully connect to the network through L2TP dialup. When the public network user (PC2) performs L2TP dialup (packets from PC2 to the LAC are forwarded through GE1/0/0), error 800 is displayed. Log in to the AR to collect L2TP debugging information. There is no L2TP debugging information on the AR.