Fixing errors generated by a security policy requires tools to verify the network traffic flow, including verifications of protocols and ports. The following CLI tools are fundamental to troubleshooting issues related to security filters.
All FortiGate units have a built-in packet sniffer (or network analyser, a feature that captures all the data packets that pass through a given network interface or device). The packet sniffer includes six levels of information numbered from verbose 1 (basic information) to verbose 6 (that incorporates a lot of information also regarding the interfaces).
The command to use is:
diagnose sniffer packet. The parameters are:
<interface>: A specific ...