Technical Tip: Default route configuration

[carabhavi]

Description

This article describes how to add a default route.

Scope

FortiGate.

Solution

Adding a default route when addressing mode is selected as manual:

1. Go to Network -> Static Routes. Typically, there is only one default route. If the static route list already contains a default route, edit it, or delete the route and add a new one.
2. Set 'Destination' to 'Subnet' and leave the destination IP address set to 0.0.0.0/0.0.0.0.
3. Set Gateway to the IP address provided by the ISP and Interface to the Internet-facing interface.
   
   

The default route could be configured using the CLI as well:

config router static
    edit 0
        set dst 0.0.0.0/0
        set gateway 172.25.176.1
        set device wan1
    end
end

Other important parameters like priority and distance also could be configured using the CLI :

config router static
    edit 1
        set distance 5
        set priority 3
    end
end

When the addressing mode is selected as DHCP or PPPoE:

• By default, the route will be created; there is no need to create a static route manually.
• By default, the distance will be assigned as 5. It is possible to change the value by navigating to Network -> Interfaces and editing the respective interface.

get router info routing-table all
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default

Routing table for VRF=0
S* 0.0.0.0/0 [5/0] via 172.31.176.254, ppp2, [1/0]
S 1.1.1.0/24 [254/0] is a summary, Null, [1/0]
C 10.1.1.0/24 is directly connected, DIAL_UP
C 10.1.1.1/32 is directly connected, DIAL_UP
C 10.5.16.0/20 is directly connected, lan
C 10.10.1.0/24 is directly connected, test_advpn
C 10.10.1.1/32 is directly connected, test_advpn
C 10.10.10.0/24 is directly connected, loopback-lan
C 10.14.0.0/20 is directly connected, wan1
C 10.68.0.0/20 is directly connected, wan2
C 172.31.176.24/32 is directly connected, ppp2
C 172.31.176.254/32 is directly connected, ppp2

Related articles:

Technical Tip: How to create or delete static routes via CLI on FortiGate

Technical Tip: Creating a static route that uses a FQDN firewall address object