A passive interface is specifically designed to monitor copied network traffic received from a switch SPAN or mirror port. Because the Secure Firewall Threat Defense device is not physically placed in the traffic path, it receives a copy of the packets for inspection but does not retransmit them. This provides network and intrusion visibility without affecting production traffic. The trade-off is that a passive deployment cannot directly block, shape, or modify the monitored traffic because the original packets continue through the switch independently. An inline deployment, by comparison, places paired interfaces directly in the forwarding path and can drop malicious traffic. Routed and transparent describe firewall forwarding modes and are not the appropriate SPAN-based IPS interface type. Therefore, a SPAN-port monitoring deployment requires a passive interface. Cisco passive-interface documentation

A file policy defines the actions that the Cisco Firepower Threat Defense (FTD) device should take when it encounters different types of files. The file policy is applied as part of an access control policy. If an access control policy does not include a file policy, the FTD device will not take any action on the files it encounters, resulting in a disposition of "unknown" for all file types except exe.
Reference:https://www.cisco.com/c/en/us/support/docs/security/firepower-ngfw/219759-configure-bypass- policies-on-the-cisco-firepow.html

Dynamic Analysis submits eligible files with an Unknown or Unavailable malware-cloud disposition to Cisco Secure Malware Analytics, formerly Cisco Threat Grid. The service executes and observes the file in a controlled environment, examines its behavior, and returns a threat score and detailed analysis report. Secure Firewall Management Center can use the returned threat score and the threshold configured in the file policy to determine whether the file should be treated as malware. Spero Analysis is different because it examines structural characteristics and generates a signature primarily for executable files. It does not provide the comprehensive sandbox-based behavioral examination described in the question. Therefore, when unknown files must be submitted to Secure Malware Analytics for deeper investigation, Dynamic Analysis is the required configuration. Cisco file-policy documentation

To configure Active Directory authentication for VPN authentication on a Cisco Secure Firewall Threat Defense (FTD) instance registered with Cisco Secure Firewall Management Center (FMC), the administrator needs to configure Realms in the System settings of the FMC. Realms in FMC are used to define the directory servers (e.g., Active Directory) and how they are used for user authentication.
Steps to configure this in FMC:
* Navigate to System > Integration > Realms and Directory.
* Add a new realm and configure the necessary details such as the directory server type (e.g., Active Directory), server address, and bind credentials.
* Test the connection to ensure it works correctly.
This setup allows the FMC to authenticate VPN users against the Active Directory, thereby enabling secure access control for VPN connections.
References: Cisco Secure Firewall Management Center Administrator Guide, Chapter on Realms Configuration.