4 troubleshooting procedures, Determining that the user address is correct, Checking whether network congestion occurs – Panasonic NN46240-710 User Manual

Page 29: Checking that the tunnel exists, 4 troubleshooting procedures -5, Troubleshooting procedure

Attention! The text in this document has been recognized automatically. To view the original document, you can use the "Original mode".

Nortel Secure Router 8000 Series

Troubleshooting - VPN___________

1 L2TP troubleshooting

1.2.4 Troubleshooting procedures

The troubleshooting procedures are as follows.

Step 1 Determining that the user address is correct

Step 2 Checking whether network congestion occurs

Step 3 Checking that the tunnel exists

Step 4 Checking the state of PPP negotiation on the LNS side

Step 5 Checking that the LAC can ping through the loopback interface of the LNS

Step 6 Checking the status of PPP negotiation on the LAC side

—End

The following sections describe the troubleshooting steps.

Determining that the user address is correct

The LNS can assign the address to the user, or the user can specify the address. If the assigned
address and the specified address are not in the same network segment, the data transmission

fails. Nortel recommends that the LNS assign the address. The two cases are as follows:

•

When the user accesses LNS with the full name, LNS checks that the correct address
pool is bound in the VT. You must configure the address pool in the AAA view correctly.
Run the remote address pool pool-number command to bind the address pool.

•

When the user accesses LNS with the domain name, LNS checks whether a correct

address pool is configured in the domain view. You can use the ip pool pool-number

first-address [ last-address ] command to configure the address pool in the domain view.

Then, use the remote address pool pool-number command in the VT interface view to

bind the address pool to this interface.

Checking whether network congestion occurs

L2TP transmits data based on the User Datagram Protocol (UDP). The UDP does not
implement error control on the packets. If you apply L2TP when the link is unstable, the data

transmission can fail.

Checking that the tunnel exists

You can use the display l2tp tunnel command to check whether the tunnel is established on

the LAC and LNC. If no corresponding tunnel exists, check the configuration using the
following methods:

Run the display this command in the L2TP group view on the LAC end to check

whether the LNS address with the start l2tp command is correctly configured. The

address should be the same as the loopback address on the LNS end. If they are different,

you need to reconfigure the LNS address.

Run the display this command in the L2TP group view on the LAC side to check

whether the LNS address is correct in the allow l2tp command. The address must be
consistent with the IP address of the loopback interface on the LNS end. If they are
inconsistent, you must reconfigure them.

Issue 5.3 (19 January 2009)

Nortel Networks Inc.

1-9