Fortinet MR8 manual NAT/Route mode with multiple external network connections

Planning the FortiGate configuration Getting started

You must configure routing to support the redundant WAN1 and WAN2 internet connections. Routing can be used to automatically redirect connections from an interface if its connection to the external network fails.

You can add firewall policies to control whether communications through the FortiGate unit operate in NAT or Route mode. Firewall policies control the flow of traffic based on the source address, destination address, and service of each packet. In NAT mode, the FortiGate unit performs network address translation before it sends the packet to the destination network. In Route mode, there is no address translation.

You typically use NAT/Route mode when the FortiGate unit is operating as a gateway between private and public networks. In this configuration, you would create NAT mode firewall policies to control traffic flowing between the internal, private network and the external, public network (usually the Internet).

If you have multiple internal networks, such as a DMZ network in addition to the internal, private network, you could create route mode firewall policies for traffic flowing between them.

Figure 6: Example NAT/Route mode network configuration

								Internal network
									192.168.1.3
	FortiGate-60 Unit							Internal
	in NAT/Route mode							192.168.1.99
	WAN1
Internet	204.23.1.5								Route mode policies
		INTERNAL
	PWR STATUS 1	2	3	4	DMZ	WAN1	WAN2		controlling traffic between
	LINK 100	LINK 100	LINK 100	LINK 100	LINK 100	LINK 100	LINK 100		internal networks.
								DMZ	DMZ network
	NAT mode policies controlling							10.10.10.1
	traffic between internal and
	external networks.
									10.10.10.2

NAT/Route mode with multiple external network connections

In NAT/Route mode, you can configure the FortiGate unit with multiple redundant connections to the external network (usually the Internet). For example, you could create the following configuration:

•WAN1 is the default interface to the external network (usually the Internet).

•WAN2 is the redundant interface to the external network. You can also use the modem interface as a redundant connection to the external network.

•Internal is the interface to the internal network.

You must configure routing to support redundant Internet connections. Routing can be used to automatically redirect connections from an interface if its connection to the external network fails.

24 01-28008-0018-20050128 Fortinet Inc.