Active client-side policy
Add an active policy to the client-side FortiGate unit by selecting Enable WAN Optimization and selecting active. Then select a WAN optimization Profile. From the CLI the policy could look like the following:
config firewall policy
edit 2
set srcintf "internal"
set dstintf "wan1"
set srcaddr "client-subnet"
set dstaddr "server-subnet"
set action accept
set schedule "always"
set service "ANY"
set utm-status enable
set av-profile default
set profile-protocol-options default
set wanopt enable
set wanopt-detection active
set wanopt-profile "default"
next
end