Fortinet 50B Selecting a modem mode, Redundant mode configuration, Stand alone mode configuration

Selecting a modem mode Configuring the modem interface

Figure 12: Example modem interface network connection

			FortiGate-50A
DC+12V
Modem	Console	USB	External	Internal

USB-to-serial converter

V.92

External modem

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.

52	FortiGate-50A/50B, FortiWiFi-50B and FortiGate-100 FortiOS 3.0 MR4 Install Guide
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