Nat/Route Mode With Multiple External Network Connections - Fortinet FortiGate FortiGate-200A Install Manual

Planning the FortiGate configuration

NAT/Route mode with multiple external network connections

32
You can add firewall policies to control whether communications through the
FortiGate unit operates 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).
Note: 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 8: NAT/Route mode network configuration for a FortiGate-200A.
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 onfiguration:
• Port 1 is the default interface to the external network (usually the Internet)
• Port 2 is the interface to the internal network
• Port 3 is the redundant interface to the external network
Figure 9: Multiple internet connection configuration for a FortiGate-400A.
Internet
FortiGate-200A, FortiGate-300A, FortiGate-400A, and FortiGate-500A FortiOS 3.0 MR4 Install Guide
192.168.1.99
WAN1
204.23.1.5
10.10.10.1
NAT policies controlling
traffic between internal
and external networks.
Port 1
Port 2
192.168.1.1
204.23.1.5
Port 3
64.83.32.45
NAT policies controlling traffic
between internal and external networks.
Configuring the FortiGate unit
Internal network
192.168.1.3
Internal
Route mode policies
controlling traffic between
Internal networks.
DMZ1
DMZ network
10.10.10.2
Internal network
192.168.1.3
01-30004-0268-20070712