Configuring

NAT vs. Transparent mode

Configuring

This section provides an overview of the operating modes of the FortiGate unit, NAT/Route and Transparent, and how to configure the FortiGate unit for each mode. There are two ways you can configure the FortiGate unit, using the web-based manager or the command line interface (CLI). This section will step through using both methods. Use whichever you are most comfortable with.

This section includes the following topics:

NAT vs. Transparent mode

Connecting to the FortiGate unit

Verify the configuration

Backing up the configuration

Additional configuration

NAT vs. Transparent mode

The FortiGate unit can run in two different modes, depending on your network infrastructure and requirements. You have a choice between NAT/Route mode and Transparent mode. Both include the same robust network security features such as antispam, antivirus, VPN and firewall policies.

NAT mode

In NAT/Route mode, the FortiGate unit is visible to the network. Like a router, all its interfaces are on different subnets.

In NAT mode, each port is on a different subnet, enabling you to have a single IP address available to the public Internet. The FortiGate unit performs network address translation before it sends and receives the packet to the destination network.

In Route mode, there is no address translation.

Figure 4: FortiGate unit in NAT mode

Internet

204.23.1.5

192.168.1.99

 

 

Router

NAT mode policies controlling traffic between internal and external networks.

Internal network

192.168.1.20

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.

FortiGate-224B FortiOS 3.0 MR6 Install Guide

 

01-30006-0451-20080815

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Fortinet 224B manual NAT vs. Transparent mode, NAT mode