Adding the OSPF interface
OSPF uses the metric called cost when determining the best route, with lower costs being preferred. Up to now in this example, only the default cost of 10 has been used. Cost can be set only in the CLI.
The new IPsec tunnel will have its OSPF cost set higher than that of the default tunnel to ensure that it is only used if the first tunnel goes down. The new tunnel could be set to a cost of 200 compared to the default cost is 10. Such a large difference in cost will ensure this new tunnel will only be used as a last resort.
If the new tunnel is called tunnel_wan2, you would enter the following on both FortiGate units:
config router ospf
config ospf-interface
edit ospf_wan2
set cost 200
set interface tunnel_wan2
set network-type point-to-point
end
end