Ipsec Lan To Lan With Pre-Shared Keys - D-Link DFL-1660 User Manual

9.2.1. IPsec LAN to LAN with
Pre-shared Keys

9.2.1. IPsec LAN to LAN with Pre-shared Keys

The objective is to create a secure means of joining two networks: a Local Network which is on the
protected side of a local firewall; and a Remote Network which is on the other side of some remote
device, located across an insecure network.
The steps for setup are as follows:
1. Create a Pre-shared Key object.
2. Optionally create a new IKE Algorithms object and/or an IPsec Algorithms object if the
default algorithm proposal lists do not provide a set of algorithms that are acceptable to the
tunnel remote end point. This will depend on the capabilities of the device at the other end of
the VPN tunnel.
3. In the Address Book create IP objects for:
• The remote VPN gateway which is the IPv4 address of the network device at the other end
of the tunnel (let's call this object remote_gw). This may or may not be another NetDefend
Firewall.
• The remote network which lies behind the remote VPN gateway (let's call this object
remote_net).
• The local network behind the NetDefend Firewall which will communicate across the
tunnel. Here we will assume that this is the predefined address lannet and this network is
attached to the NetDefendOS lan interface which has the IPv4 address lan_ip.
4. Create an IPsec Tunnel object (let's call this object ipsec_tunnel). Specify the following tunnel
parameters:
• Set Local Network to lannet.
• Set Remote Network to remote_net.
• Set Remote Endpoint to remote_gw.
• Set Encapsulation mode to Tunnel.
• Choose the IKE and IPsec algorithm proposal lists to be used.
• For Authentication select the Pre-shared Key object defined in step (1) above.
The IPsec Tunnel object can be treated exactly like any NetDefendOS Interface object in later
steps.
5. Set up two IP rules in the IP rule set for the tunnel:
• An Allow rule for outbound traffic that has the previously defined ipsec_tunnel object as
the Destination Interface. The rule's Destination Network is the remote network
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Chapter 9. VPN