Chapter 10 Install and System Administration for FortiOS 5.0 : Advanced concepts : Modem : Modes : Ping server
  
Ping server
Adding a ping server is required for routing fail over traffic. A ping server will confirm the connectivity of the device’s interface.
For low-end FortiGate units, go to System > Admin > Settings and enable Dynamic Routing before continuing.
To add a ping server - web-based manager
1. Go to Router > Static > Settings and select Create New.
2. Select the Interface that will send ping requests.
3. For the Ping Server field, enter the IP address of a server that the FortiGate unit will send ping requests to. This is typically a next hop router or gateway device.
4. Select the Detect Protocol type ICMP Ping.
5. For the Ping Interval, enter the number of seconds to send ping requests.
6. For the Failover Threshold, enter the number of lost pings is acceptable before the port is determined to be down.
7. Select OK.
To add a ping server - CLI
config router gwdetect
edit wan1
set server <ISP_IP_address>
set failtime <failure_count>
set interval <seconds>
end
See Also
Configuring stand alone mode
Configuring redundant mode
Modes
Modem