Nat/Route Mode; Transparent Mode - Fortinet FortiGate FortiGate-5005FA2 Security System Manual

Planning the configuration

NAT/Route mode

Transparent mode

18
In NAT/Route mode, the FortiGate-5005FA2 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-5005FA2 security
system is deployed as a gateway between private and public networks. In the
default NAT/Route mode configuration, the FortiGate-5005FA2 security system
functions as a firewall. Firewall policies control communications through the
FortiGate-5005FA2 security system. No traffic can pass through the
FortiGate-5005FA2 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 3: Example FortiGate-5005FA2 module operating in NAT/Route mode
NAT mode policies
controlling traffic between
internal and external
204.23.1.2
networks.
ACT
LINK
ACT
LINK
CONSOLE
Internal 192.168.1.99
network
Route mode policies
controlling traffic between
Internal networks.
In Transparent mode, the FortiGate-5005FA2 security system is invisible to the
network. All of the FortiGate-5005FA2 interfaces are connected to different
segments of the same network. In Transparent mode you only have to configure a
management IP address so that you can connect to the FortiGate-5005FA2
security system to make configuration changes and so the FortiGate-5005FA2
security system can connect to external services such as the FortiGuard
Distribution Network (FDN).
Internet
port2
FortiGate-5005FA2 module
in NAT/Route mode
USB USB 7 8
1 2 3 4 5 6
OOS ACC STATUS IPM
port1 port3
10.10.10.1
FortiGate-5005FA2 Security System Guide
Quick Configuration Guide
NAT mode policies
controlling traffic between
internal and external
networks.
Internal
network
01-30000-0377-20070201