Nat/Route Mode With Multiple External Network Connections - Fortinet FortiGate FortiGate-100 Install Manual

Planning the FortiGate configuration

NAT/Route mode with multiple external network connections

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You typically use NAT/Route mode when the FortiGate unit is operating as a
gateway between private and public networks. In this configuration, you create
NAT mode firewall policies to control traffic flowing between the internal, private
network and the external, public network (usually the Internet).
Figure 8: Example NAT/Route mode network configuration for a FortiGate-50A.
.
Internet
Router
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:
• External or WAN1 is the default interface to the external network (usually the
Internet)
• Modem is the redundant interface to the external network for the
FortiGate-50A
• WAN2 is the redundant interface to the external network on the FortiGate-50B
and FortiWiFi-50B.
• DMZ is the redundant interface to the external network on the FortiGate-100
• Internal is the interface to the internal network
You must configure routing to support redundant Internet connections. Routing
can automatically redirect connections from an interface if its connection to the
external network fails.
Otherwise, security policy configuration is similar to a NAT/Route mode
configuration with a single Internet connection. You would create NAT mode
firewall policies to control traffic flowing between the internal, private network and
the external, public network (usually the Internet).
Figure 9: NAT/Route multiple internet connection configuration for a FortiGate-50A
.
Internet
MODEM
FortiGate-50A/50B, FortiWiFi-50B and FortiGate-100 FortiOS 3.0 MR4 Install Guide
Internal
External
204.23.1.5 192.168.1.99
FortiGate-50A
NAT mode policies controlling
traffic between internal and
external networks.
External
Internal
204.23.1.5
192.168.1.1
FortiGate-50A
NAT mode policies controlling
traffic between internal and
external networks.
Configuring the FortiGate unit
Internal network
192.168.1.3
Internal network
192.168.1.3
01-30004-0265-20070831