Adjusting the route costs
On both FortiGate units, the cost of the route through WAN2 is adjusted higher so that this route will only be used if the route through WAN1 is unavailable. The default cost is 10. The WAN2 route will be changed to a cost of 200.
On both FortiGate units:
config router ospf
config ospf-interface
edit "WAN2_higher_cost"
set cost 200
set interface "wan2"
end
Now both FortiGate units use only the WAN1 route:
FortiGate 1:
FGT1 # get router info routing-table ospf
O*E2 0.0.0.0/0 [110/10] via 10.182.0.187, wan1, 00:00:40
O 192.168.182.0/23 [110/20] via 10.182.0.187, wan1, 00:00:40
FortiGate 2:
FGT2 # get router info routing-table ospf
O 10.160.0.0/23 [110/20] via 10.182.0.57, wan1, 00:09:37
LSDB check on FortiGate 1:
FGT1 # get router info ospf database router lsa
Router Link States (Area 0.0.0.0)
LS age: 81
Options: 0x2 (*|-|-|-|-|-|E|-)
Flags: 0x0
LS Type: router-LSA
Link State ID: 10.1.1.1
Advertising Router: 10.1.1.1
LS Seq Number: 8000000b
Checksum: 0xe637
Length: 60
Number of Links: 3
Link connected to: Stub Network
(Link ID) Network/subnet number: 10.160.0.0
(Link Data) Network Mask: 255.255.254.0
Number of TOS metrics: 0
TOS 0 Metric: 10
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.183.0.187
(Link Data) Router Interface address: 10.183.0.57
Number of TOS metrics: 0
TOS 0 Metric: 200
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.182.0.57
(Link Data) Router Interface address: 10.182.0.57
Number of TOS metrics: 0
TOS 0 Metric: 10
LS age: 83
Options: 0x2 (*|-|-|-|-|-|E|-)
Flags: 0x2 : ASBR
LS Type: router-LSA
Link State ID: 10.2.2.2
Advertising Router: 10.2.2.2
LS Seq Number: 8000000e
Checksum: 0xfc9b
Length: 60
Number of Links: 3
Link connected to: Stub Network
(Link ID) Network/subnet number: 192.168.182.0
(Link Data) Network Mask: 255.255.254.0
Number of TOS metrics: 0
TOS 0 Metric: 10
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.183.0.187
(Link Data) Router Interface address: 10.183.0.187
Number of TOS metrics: 0
TOS 0 Metric: 200
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.182.0.57
(Link Data) Router Interface address: 10.182.0.187
Number of TOS metrics: 0
TOS 0 Metric: 10