Network Router User Manual

FortiGate-50A/50B, FortiWiFi-50B and FortiGate-100 FortiOS 3.0 MR4 Install Guide
52 01-30004-0265-20070831
Selecting a modem mode Configuring the modem interface
Figure 12: Example modem interface network connection
Selecting a modem mode
The modem interface can work in one of two modes:
• redundant mode
• stand alone mode
Redundant mode configuration
The redundant modem interface serves as a backup to the Ethernet interface. If
that Ethernet interface disconnects from its network, the modem automatically
dials the configured dial-up account(s). When the modem connects to a dial-up
account, the FortiGate unit routes IP packets normally destined for the selected
Ethernet interface to the modem interface. During this time, the unit pings the
Ethernet connection to check when it is back online.
When the Ethernet interface can connect to its network again, the FortiGate unit
disconnects the modem interface and switches back to the Ethernet interface.
For the FortiGate unit to switch from an Ethernet interface to the modem you must
select the name of the interface in the modem configuration and configure a ping
server for that interface. You must also configure firewall policies for connections
between the modem interface and other FortiGate interfaces.
Stand alone mode configuration
In stand alone mode, you manually connect the modem to a dial-up account. The
modem interface operates as the primary connection to the Internet. The
FortiGate unit routes traffic through the modem interface, which remains
permanently connected to the dial-up account.
If the connection to the dial-up account fails, the FortiGate unit modem
automatically redials the number. The modem redials the ISP number based on
the amount of times specified by the redial limit, or until it connects to a dial-up
account.
Internal
External
DC+12V
USB
Modem Console
V.9 2
External modem
USB-to-serial converter
FortiGate-50A