Configure Modem Failover
You can configure your Firebox to send traffic through a modem when the Firebox cannot send traffic with any external interface. For a list of supported modems and Fireboxes, see About Modem Interfaces.
If your Firebox was configured for modem failover, when you upgrade your Firebox to Fireware v12.1, the modem configuration is automatically converted to an external interface with failover enabled.
You can also configure branch office VPN connections to fail over to a modem interface. For more information, see Configure VPN Modem Failover.
To add a modem interface as a multi-WAN participant, see Configure the Failover Multi-WAN Method.
In Fireware v12.0.2 and lower, the steps to configure modem failover and link monitor settings are different. For more information, see Configure Modem Failover in Fireware v12.0.2 and lower in the WatchGuard Knowledge Base.