How to establish IPSec between fortigate and PFsense

[secsupport]

The remote office has Pfsence which is behind the router and has no public ip(wan interface) it's on local subnet of the router, FortiGate  is direct with wan interface stati

so how we can have IPSec in this scenario 

kindly explain 

[kcheng · Accepted solution]

Hi, 

You will probably need a port forwarding from the router at the remote side to perform NAT from the public IP to the Pfsense behind that router. It would not be possible to form IPSec tunnel if FortiGate does not have route and connectivity towards the remote device. The remote gateway is required to be reachable from FortiGate before IPSec tunnel can be formed.

[secsupport]

Dear @kcheng I did it successfully but just select the LAN port on pfsense side like we select the WAN interface normally but in this case was different (server-client scenario)