2) Policy & Object > Firewall Policy > Security Profiles > Apply of IPS Sensor after IPS enable
3. How IPS Quarantine malware, and How IPS Identify is it malicious IPs or not and many more. Behavior so that FortiGuard Server can internally verify and classify as malicious IPs to block them. Fortigate gets updates from the server in real time. You can inquire about false positives at https://www.fortiguard.com/faq.
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.