Troubleshooting scenarios

The following table is intended to help you diagnose common problems and provides links to the corresponding troubleshooting topics:

Problem	Probable cause	Recommended action
Hardware connections	Are all of the cables and interfaces connected properly? Is the LED for the interface green?	Checking the hardware connections
FortiOS network settings	If you are having problems connecting to the management interface, is your protocol enabled on the interface for administrative access? Does the interface have an IP address?	Checking FortiOS network settings
CPU and memory resources	Is the CPU running at almost 100 percent usage? Is your FortiGate running low on memory?	Checking CPU and memory resources
Modem status	Is the modem connected? Are there PPP issues?	Checking the modem status
Ping and traceroute	Is the FortiGate experiencing complete packet loss?	Running ping and traceroute
Logs	Do you need to identify a problem?	Checking the logs
Contents of the routing table (in NAT mode)	Are there routes in the routing table for default and static routes? Do all connected subnets have a route in the routing table? Does a route have a higher priority than it should?	Verifying routing table contents in NAT mode
Traffic routes	Is the traffic routed correctly?	Verifying the correct route is being used
Firewall policies	Is the correct firewall policy applied to the expected traffic?	Verifying the correct firewall policy is being used
Bridging information in transparent mode	Are you having problems in transparent mode?	Checking the bridging information in transparent mode
Number of sessions used by UTM proxy	Have you reached the maximum number of sessions for a protocol? Are new sessions failing to start for a certain protocol?	Checking the number of sessions that UTM proxy uses
Firewall session list	Are there active firewall sessions?	Using a session table
Wireless Network	Is the wireless network working properly?	Checking wireless information
FortiGuard connectivity	Is the FortiGate communicating properly with FortiGuard?	Verifying connectivity to FortiGuard
Sniffer trace	Is traffic entering the FortiGate? Does the traffic arrive on the expected interface? Is the ARP resolution correct for the next-hop destination? Is the traffic exiting the FortiGate to the destination as expected? Is the FortiGate sending traffic back to the originator?	Performing a sniffer trace (CLI and packet capture)
Packet flow	Is traffic entering or leaving the FortiGate as expected?	Debugging the packet flow