Creating Gre Tunnel on Fortigate

config system gre-tunnel

    edit "tunnelname"

        set interface "wan1"

        set local-gw 192.168.10.13

        set remote-gw 192.168.1.62

    next

end

config system interface

    edit "tunnelname"

        set vdom "root"

        set ip 1.1.1.2 255.255.255.255

        set allowaccess ping

        set type tunnel

        set remote-ip 1.1.1.1

        set snmp-index 9

        set interface "wan1"

        set mtu 1500

    next

end

Open the policies after the same.

    1)    Internal  ---> Tunnel

2  2)   Tunnel    ---> Internal