In a passive IPS deployment for a Cisco Secure Firewall Threat Defense (FTD) device, the administrator must configure the interface to operate in passive mode. This involves setting the interface mode, associating it with a security zone, enabling the interface, and setting the MTU parameter.

Steps:

Set the interface mode to passive:

In FMC, navigate toDevices > Device Management.

Select the FTD device and configure the relevant interface.

Set the interface mode to " Passive. "

Associate the interface with a security zone:

Create or select an appropriate security zone.

Assign the passive interface to this security zone.

Enable the interface:

Ensure the interface is enabled to receive traffic.

Set the MTU parameter:

Configure the Maximum Transmission Unit (MTU) parameter as required.

This ensures that the FTD device can inspect traffic passively without impacting the network flow.