Chapter 13 Logging and Reporting : Logging and reporting overview : FortiOS features available for logging : Network scan
  
Network scan
Network scan logs are recorded when a scheduled scan of the network occurs. These log messages provide detailed information about the network’s vulnerabilities regarding software, as well as the discovery of any further vulnerabilities.
A scheduled scan must be configured and logging enabled within the Event Log settings, for the FortiGate unit to record these log messages.