Fortinet Version 3.0 manual Connecting the FortiBridge unit

Example FortiBridge application FortiBridge operating principles

The FortiGate unit acts as an extra layer of protection for your internal network. While it is operating, the FortiGate unit protects the internal network from threats originating on the Internet. All users on the internal network connect through the FortiGate unit to the Internet. This also means that if a failure or other interruption caused the FortiGate unit to stop functioning, users on the internal network would not be able to connect to the Internet.

You can install a FortiBridge unit to maintain internet connectivity for the internal network if the FortiGate unit stops functioning. The FortiBridge unit provides fail open protection for your network by bypassing the FortiGate unit if a failure occurs.

Connecting the FortiBridge unit

Operating in normal mode, the FortiBridge unit functions like a layer-2 bridge, passing all traffic to the FortiGate unit. The FortiGate unit processes the traffic, which then passes through the FortiBridge unit again and then to its final destination.

In most cases, you do not have to make changes to the FortiGate unit configuration or to the network to add a FortiBridge unit. The only network requirement for FortiBridge is the availability of a single management IP address for the FortiBridge unit. The FortiBridge management IP address is required in addition to the FortiGate management IP address.

The connection procedure is different depending on whether the FortiBridge unit uses copper gigabit ethernet network connections or fiber gigabit ethernet network connections. This section includes the following connection procedures:

•Connecting the FortiBridge-1000 (copper gigabit ethernet)

•Connecting the FortiBridge-1000F (fiber gigabit ethernet)

Figure 3: FortiBridge unit providing fail open protection

(Normal mode)

Internal network

INT 1

INT 2

Internal

EXT 1	Internet
EXT 2	Router
External

(Transparent mode)

Connecting the FortiBridge-1000 (copper gigabit ethernet)

The FortiBridge-1000 unit contains 4 auto-sensing 10/100/1000 Ethernet interfaces that connect to the internal and external networks and to the FortiGate interfaces that were connected to these networks. Use the following steps to connect a FortiBridge-1000 unit to the network as shown in Figure 3.

Note: Normally, you would use straight-through ethernet cables to connect the FortiBridge-1000 unit to the FortiGate unit and to your networks. However, for some connections you may need a crossover ethernet cable (for example, for compatibility with network devices that do not support Auto MDI/MDIX).

10	FortiBridge Version 3.0 Administration Guide
	09-30000-0163-20061109