Fortigate GRE tunnel

I like to work with GRE most of all because it's the easiest way to connect 2 firewalls/routers, in case there is no need for tough encryption

So lets create a tunnel in a Forti firewall,

·         First must use the CLI to create the tunnel itself

config system gre-tunnel

    edit "GRE-Test"

        set interface "wan1"

        set local-gw [WAN IP]

        set remote-gw [Peers' IP]

    next

end

the rest can be done via GUI, I will post both GUI and CLI versions.

Configuring via GUI will look like this :

·         Configure the interface

·         And add rules for the tunnel

To continue via CLI use:

config system interface

    edit "GRE-Test"

        set vdom "root"

        set ip 1.1.1.1 255.255.255.255

        set allowaccess ping

        set type tunnel

        set remote-ip 1.1.1.2

        set interface "wan1"

    next

endconfig firewall policy

    edit 3

        set srcintf "GRE-Test"

        set dstintf "internal"

            set srcaddr "all"

            set dstaddr "all"

        set action accept

        set logtraffic-app disable

        set schedule "always"

            set service "ANY"

    next

config firewall policy

    edit 4

        set srcintf "internal"

        set dstintf "GRE-Test"

            set srcaddr "all"

            set dstaddr "all"

        set action accept

        set logtraffic-app disable

        set schedule "always"

            set service "ANY"

    next

that’s it, I suggest adding a dynamic routing protocol  to learn the networks on each end,

I prefer OSPF for this configuration, done from Router > Dynamic > OSPF

And using settings like this :

Now we have full connectivity between 2 sites without using encryption.

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