execute : traceroute
 
traceroute
Test the connection between the FortiGate unit and another network device, and display information about the network hops between the device and the FortiGate unit.
Syntax
execute traceroute {<ip_address> | <host-name>}
Example
This example shows how to test the connection with http://docs.forticare.com. In this example the traceroute command times out after the first hop indicating a possible problem.
#execute traceoute docs.forticare.com
traceroute to docs.forticare.com (65.39.139.196), 30 hops max, 38 byte packets
1 172.20.120.2 (172.20.120.2) 0.324 ms 0.427 ms 0.360 ms
 2  * * *
If your FortiGate unit is not connected to a working DNS server, you will not be able to connect to remote host-named locations with traceroute.