L2Tp Vpn Troubleshooting Tips - ZyXEL Communications SBG5500 Series User Manual

Table 77 Configuration > VPN > L2TP VPN > Client
LABEL
Management IP Address
Local Host Name
Tunnel Auth
Tunnel Secret
PPP Setup
MPPE Enable
Auth Type
Username
Password
Interface Group NAT Setup
Default
Apply
Reset

10.7.3 L2TP VPN Troubleshooting Tips

This section lists the common troubleshooting tips for L2TP VPN.
A L2TP client device (such as a PC, smart phone, tablet) cannot connect to the SBG.
1
TIP: This could be due to one of the following reasons:
a. The client device is not connected to the Internet successfully.
Action: Check the client device's Internet connection.
Chapter 10 VPN
DESCRIPTION
Enter the SBG's public routable IP address for management purposes, and an
administrator will be able to reach the SBG via L2TP VPN connection and the
address input here.
Enter the L2TP local host name.
When performing tunnel authentication on the LNS (L2TP Network Server), please
select the check box to enable tunnel authentication, and enter a valid Tunnel
Secret in the next column.
Enter a valid Tunnel Secret consisting of 4-64 characters, and the following special
characters are not allowed: '/\=".
Click the check box to use MPPE, Microsoft Point to Point Encryption. It enables 40-bit
encryption as well as 128-bit encryption.
Note: PPP CHAP must be enabled as well.
Select PAP or/and CHAP as your authentication method(s).
PAP (Password Authentication Protocol ) - The L2TP server will crosscheck the
username and password sent by the client with the database for authentication
purposes.
CHAP (Challenge Handshake Authentication Protocol) - When it's enabled, MS-
CHAP and MS-CHAP-v2 are both supported. Also, CHAP needs to be enabled if you
wish to activate MPPE.
Enter the username for PPP authentication. It must be consistent with the
configuration made on LNS (L2TP Network Server). Otherwise the L2TP VPN
connection will not be established.
Enter the password for PPP authentication. It must be consistent with the
configuration made on LNS (L2TP Network Server). Otherwise the L2TP VPN
connection will not be established.
Select None, NAT, or Address Mapping to apply to the L2TP VPN connection.
None - NAT is not applied to the L2TP VPN connection.
NAT - Select this option to turn on the NAT function on the VPN connection.
Address Mapping - Select this option to apply the specified address mapping rule(s)
to the VPN connection. The address mapping rules are configured using the
Configuration > NAT > Address Mapping screen.
Click Apply to save your changes back to the SBG.
Click Reset to restore your previous settings.
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