D-Link DFL-1600 User Manual page 257

22.2. PPTP/ L2TP
4. IPsec Tunnel
Next step is to configure the IPsec tunnel.
Interfaces IPsec Tunnels
General
Enter the following:
Name: L2TPIPsecTunnel
Local Network: This is the local network that the remote users will
connect to. As we are going to use L2TP this is the IP the L2TP clients
will connect to. In this case 10.0.0.1
Remote Network: The firewall looks at this field and compares it to the
roaming user's source IP address in order to allow connections only from
the configured local net to remote net. However, in this scenario, clients
should be allowed to roam in from everywhere. Thus, this field is set to
all-nets (0.0.0.0/0). That means that virtually all existing IPv4-addresses
are allowed to connect.
Remote Endpoint: (None)
Encapsulation Mode: Transport
Algorithms
IKE Algorithms: Medium
IPsec Algorithms: Medium
Authentication
Pre-Shared Key: Select the pre-shared key created earlier, L2TPKey in
this case.
Routing
Automatic Routing
The IPsec tunnel needs to be configured to dynamically add routes to the
remote network when the tunnel is established. This is done under the
Routing tab. Dynamically add route to the remote network when a
tunnel is established: Enable
Then click OK
Add
D-Link Firewalls User's Guide
IPsec Tunnel:
237