Fortinet Version 3.0 - Manual (Page 14)

FortiBridge Version 3.0 Administration Guide
14 09-30000-0163-20061109
Bypass mode operation FortiBridge operating principles
Bypass mode operation
When the FortiBridge unit operates in bypass mode, the FortiBridge INT 1 and
EXT 1 interfaces are directly connected. All traffic between the internal and
external network segments flows, whether or not the FortiGate unit is operating
normally.
Because the INT 1 and EXT 1 interfaces are directly connected, you cannot use
Telnet or SSH to connect to the FortiBridge CLI. Instead you must use a console
connection.
The FortiBridge unit remains in bypass mode even if the FortiGate unit recovers.
To restore the FortiGate unit, you must manually switch the FortiBridge unit back
to normal mode. You can switch the FortiBridge unit to normal mode by pressing
the mode switch on the FortiBridge front panel or by using a console connection to
the CLI and entering the command execute switch-mode. You can also use
the mode switch and the execute switch-mode command to manually switch
the FortiBridge unit from normal mode to bypass mode.
Figure 6: FortiBridge unit operating in bypass mode
When the FortiBridge unit is operating in bypass mode you can still connect to the
FortiBridge CLI and manage the FortiBridge unit (for example to switch the
FortiBridge unit to normal mode). When the FortiBridge unit operates in bypass
mode, you cannot connect to the FortiGate interfaces that are connected to the
FortiBridge unit.
FortiBridge power failure
If a power failure occurs and the FortiBridge unit loses power, zero power fail open
technology causes FortiBridge unit to fail open. The FortiBridge unit bypasses the
FortiGate unit and all traffic passes between the FortiBridge INT 1 and EXT 1
interfaces. If power is restored to the FortiBridge unit, it starts up in bypass mode
and then switches to normal mode when its start up sequence is complete,
reconnecting the FortiGate unit to the network.
Router
INT 1
INT 2
EXT 1
EXT 2
Internal External
Internal network
Internet
(Transparent mode)
(Bypass mode)
Note: The FortiBridge-1000F contains a battery to keep the fibers lit in fail open mode. If
the FortiBridge-1000F unit loses power, the battery will power the fail open condition for
approximately three hours. When power is restored, the battery requires approximately
three hours to recharge if completely drained. The FortiBridge-1000 unit does not use a
battery and can maintain a fail open condition indefinitely.