Re: fortigate 90d port forwarding
Shame the router/gateway make/model information wasn't provided - the answer may depend on what the ISP router is expecting for local and external IP address. But it's logically to assume the local IP would be that of the IP assigned to the Fortigate by the ISP router and start-end ports would be 443. The external IP is likely the "outside" IP address you plan to use to connect to your fgt from and the start/end port trigger, which could be port 443.
NSE4/FMG-VM64/FortiAnalyzer-VM/5.4/6.0 (FWF40C/FW92D/FGT200D/FGT101E)/ FAP220B/221C