IPSec - BINAT (NAT before IPSec)

Assume company A has local LAN and company B has local LAN Also we assume that on both sides the other networks are already in use, e.g. in company A the network is used for Voice and in company B network is used for Guest Wi-Fi.

We have to define new networks for the Phase 2 with unused ones and create NAT entries to reach the final systems.

To make it easier we create a Phase2 with company A using as Local Network and as Remote Network and with company B using as Local network and as Remote Network. Now we need to add on each side the local LAN in the field “Manual SPD entries”. So for company A we set in the field and for B This allows the NAT process to speak with the Security Policy Database.

Finally we have to create NAT entries since a client in LAN A ( tries to reach, but this address has to be rewritten to on Firewall B.

Create the rule like in the screenshot and vice versa on Firewall A: