User's Manual

VPN
Configuring the L2TP Server
Cisco ISA500 Series Integrated Security Appliance Administrator Guide 267
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STEP 2 Click On to enable L2TP server, or click Off to disable it.
STEP 3 If you enable L2TP, enter the following information:
• Listen WAN Interface: Choose the WAN interface on which the L2TP server
listens to accept the incoming L2TP VPN connection.
• User Name: Enter the user name that all L2TP clients use to access the L2TP
server.
• Password: Enter the password that all L2TP clients use to access the L2TP
server.
NOTE All L2TP clients use the same user name and password to log into the
L2TP server.
• MTU: Enter the MTU size in bytes that can be sent over the network (the
range from 128 to 1400 bytes). The default is 1400 bytes.
• Authentication Method: You can choose either CHAP or PAP, or both to
authenticate to the L2TP clients. Click On to enable CHAP or PAP, or click Off
to disable it.
• Local Service IP: Enter the IP address of the established PPP link.
• Address Pool: The L2TP server assigns IP addresses to L2TP clients. Enter
the starting IP address in the Start IP field and the ending IP address in the
End IP field.
• DNS1 IP: Enter the IP address of the primary DNS server.
• DNS2 IP: Optionally, enter the IP address of the secondary DNS server.
• Enable over IPSec: Click On to enable the data encryption over the IPSec
VPN tunnel, or click Off to disable it.
• Preshare Key: The data encryption over the IPSec VPN tunnel uses a pre-
shared key for authentication. If you enable Enable over IPSec, enter the
desired value, which the L2TP clients must provide to establish a connection.
The pre-shared key must be entered exactly the same here and on the L2TP
clients.
STEP 4 Click Save to apply your settings.