Fortinet FortiGate 100 - Manual (Page 52)

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Fortinet Inc.
Destination based routing examples NAT/Route mode installation
Using the CLI
1 Add the route to the routing table.
set system route number 0 dst 0.0.0.0 0.0.0.0 gw1 1.1.1.1
dev1 external gw2 2.2.2.1 dev2 dmz
Load sharing
You can also configure destination routing to direct traffic through both gateways at
the same time. If users on your internal network connect to the networks of ISP1 and
ISP2, you can add routes for each of these destinations. Each route can include a
backup destination to the network of the other ISP.
The first route directs all traffic destined for the 100.100.100.0 network to gateway 1
with the IP address 1.1.1.1. If this router is down, traffic destined for the 100.100.100.0
network is re-directed to gateway 2 with the IP address 2.2.2.1.
Load sharing and primary and secondary connections
You can combine these routes into a more complete multiple internet connection
configuration. In the topology shown in
Figure 8 on page 50 , users on the Internal
network would connect to the Internet to access web pages and other Internet
resources. However, they may also connect to services, such as email, provided by
their ISPs. You can combine the routes described in the previous examples to provide
users with a primary and backup connection to the Internet, while at the same time
routing traffic to each ISP network as required.
The routing described below allows a user on the internal network to connect to the
Internet through gateway 1 and ISP1. At the same time, this user can also connect
through the DMZ interface to gateway 2 to access a mail server maintained by ISP2.
Adding the routes using the web-based manager
1 Go to System > Network > Routing Table.
2 Select New to add the default route for primary and backup links to the Internet.
• Destination IP: 0.0.0.0
• Mask: 0.0.0.0
• Gateway #1: 1.1.1.1
• Gateway #2: 2.2.2.1
• Device #1: external
• Device #2: dmz
• Select OK.
Table 13: Route for primary and backup links
Destination IP‘ Mask Gateway #1 Device #1 Gateway #2 Device #2
0.0.0.0 0.0.0.0 1.1.1.1 external 2.2.2.1 dmz
Table 14: Load sharing routes
Destination IP‘ Mask Gateway #1 Device #1 Gateway #2 Device #2
100.100.100.0 255.255.255.0 1.1.1.1 external 2.2.2.1 dmz
200.200.200.0 255.255.255.0 2.2.2.1 dmz 1.1.1.1 external