Nat/Route Mode With Multiple External Network Connections - Fortinet FortiGate 60 Installation Manual

Planning the FortiGate configuration

NAT/Route mode with multiple external network connections

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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
Internet
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.
01-28008-0018-20050128
FortiGate-60 Unit
in NAT/Route mode
WAN1
204.23.1.5
INTERNAL
PWR STATUS 1 2 3
LINK 100 LINK 100 LINK 100
NAT mode policies controlling
traffic between internal and
external networks.
Internal network
Internal
192.168.1.99
4 DMZ WAN1 WAN2
LINK 100 LINK 100 LINK 100 LINK 100
DMZ
DMZ network
10.10.10.1
Getting started
192.168.1.3
Route mode policies
controlling traffic between
internal networks.
10.10.10.2
Fortinet Inc.