To change the mode of a Cisco Secure Firewall Threat Defense (FTD) device in the Cisco Secure Firewall Management Center (FMC) inventory, the engineer must follow these steps:

Register the Secure FTD with Secure FMC.

Change the firewall mode.

Deregister the Secure FTD device from Secure FMC.

To perform these actions, accessing the Secure FTD CLI from the console port is necessary. This allows the engineer to execute the required commands to change the firewall mode and manage the registration status of the FTD device.

Steps:

Connect to the Secure FTD device via the console port.

Access the CLI and execute the command to change the firewall mode (configure firewall-mode).

Deregister the device from FMC if needed.

Register or re-register the device with FMC as required.