For traffic that does not match any configured firewall policy, what is the default action taken by the FortiGate?

The default action taken by the FortiGate for traffic that does not match any configured firewall policy is to block the traffic and not generate a log entry. This means that if there are no explicit policies allowing the traffic, the FortiGate will prevent it from passing through, enhancing security by not letting unauthorized or unrecognized traffic enter or exit the network.

Blocking such unmatched traffic helps protect the network from potential threats or unauthorized access attempts. Not generating a log for this action is typically a design choice to avoid cluttering log files with unimportant entries for traffic that does not meet any defined criteria, focusing logging resources on actual threats or relevant traffic that is processed by configured policies.