Reference

https://community.fortinet.com/fortigate-3/unable-to-configure-ip-address-in-vpn-tunnel-interface-in-fortios-7-6-8-231009

Scope

7.6.8

Situation

# FGT Web GUI沒有辦法設定Tunnel IP 
FGT Web GUI cannot setup tunnel IP.

Solution

[1]
# 登入並開啟CLI
Log in Fortigate WebUI > CLI

[2]
# 設定Tunnel介面IP
config system interface
    edit <tunnel-interface>
        set ip <ipaddress> 255.255.255.255
        set remote-ip <remoteIP> <subnet mask>
end

Check

config system interface
    edit <tunnel-interface>
        show
end