Fortinet FortiGate-800 - Manual (Page 37)

Getting started Planning the FortiGate configuration
FortiGate-800 Installation and Configuration Guide
37
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:
• External is the default interface to the external network (usually the Internet).
• Interface 1 is the redundant interface to the external network.
• Internal is the interface to the internal network.
• DMZ is the interface to the DMZ 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.
Otherwise, security policy configuration is similar to a NAT/Route mode configuration
with a single Internet connection. You would create NAT mode 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 policies for traffic flowing
between them.
Figure 5: Example NAT/Route multiple internet connection configuration
Transparent mode
In Transparent mode, the FortiGate unit is invisible to the network. Similar to a
network bridge, all FortiGate interfaces must be on the same subnet. You only have to
configure a management IP address so that you can make configuration changes.
The management IP address is also used for antivirus and attack definition updates.
You typically use the FortiGate unit in Transparent mode on a private network behind
an existing firewall or behind a router. The FortiGate unit performs firewall functions as
well as antivirus and content scanning but not VPN.
FortiGate-800 Unit
in NAT/Route mode
Route mode policies
controlling traffic between
internal networks.
Internal network
DMZ network
Internal
192.168.1.1
DMZ
10.10.10.2
192.168.1.3
10.10.10.23
NAT mode policies controlling
traffic between internal and
external networks.
External
204.23.1.5
Port 1
64.83.32.45
Internet
Esc Enter CONSOLE I N T E R N A L E X T E R N A L D M Z HA 1 2 3 4 USB
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