FortiGate-5001FA2-LENC Security System Guide
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Planning the configuration Quick Configuration Guide
Planning the configuration
Before beginning to configure your FortiGate-5001FA2-LENC security system,
you need to plan how to integrate the system into your network. Your configuration
plan depends on the operating mode that you select: NAT/Route mode (the
default) or Transparent mode.

NAT/Route mode

In NAT/Route mode, the FortiGate-5001FA2-LENC security system is visible to
the networks that it is connected to. Each interface connected to a network must
be configured with an IP address that is valid for that network. In many
configurations, in NAT/Route mode all of the FortiGate interfaces are on different
networks, and each network is on a separate subnet.
You would typically use NAT/Route mode when the FortiGate-5001FA2-LENC
security system is deployed as a gateway between private and public networks. In
the default NAT/Route mode configuration, the FortiGate-5001FA2-LENC security
system functions as a firewall. Firewall policies control communications through
the FortiGate-5001FA2-LENC security system. No traffic can pass through the
FortiGate-5001FA2-LENC security system until you add firewall policies.
In NAT/Route mode, firewall policies can operate in NAT mode or in Route mode.
In NAT mode, the FortiGate firewall performs network address translation before
IP packets are sent to the destination network. In Route mode, no translation
takes place.
Figure 7: Example FortiGate-5001FA2-LENC board operating in NAT/Route mode
FortiGate-5001FA2-LENC
board in NAT/Route mode
port3
10.10.10.1
port1
192.168.1.99
Route mode policies
controlling traffic between
Internal networks.
NAT mode policies
controlling traffic between
internal and external
networks.
NAT mode policies
controlling traffic between
internal and external
networks.
port2
204.23.1.2
Internal
network
Internal
network
Internet