To deploy a Cisco FTD device that meets the requirements of the question, the engineer must use transparent mode with a management interface. Transparent mode is a firewall configuration in which the FTD device acts as a "bump in the wire" or a "stealth firewall" and is not seen as a router hop to connected devices. In transparent mode, the FTD device can examine traffic without requiring network changes that will disrupt end users, such as changing IP addresses or routingconfigurations1. A management interface is a dedicated interface that is used for managing the FTD device and separating management traffic from data traffic. A management interface can be configured to allow SSH access for remote administration, which is more secure than Telnet2.
The other options are incorrect because:
* Routed mode is a firewall configuration in which the FTD device acts as a router and performs address translation and routing for connected networks. Routed mode requires network changes that may disrupt end users, such as changing IP addresses or routing configurations1. A diagnostic interface is a special interface that is used for troubleshooting and capturing traffic on the FTD device. A diagnostic interface does not separate management traffic from data traffic or allow SSH access for remote administration.
* Transparent mode with a data interface does not meet the requirement of separating management traffic from data traffic. A data interface is a regular interface that is used for passing and inspecting traffic on the FTD device. A data interface does not allow SSH access for remote administration2.
* Routed mode with a bridge virtual interface (BVI) does not meet the requirement of examining traffic without requiring network changes that will disrupt end users. A BVI is a logical interface that acts as a container for one or more physical or logical interfaces that belong to the same layer 2 broadcast domain. A BVI allows the FTD device to route between different bridge groups on the same security module/engine. However, routed mode still requires network changes that may disrupt end users, such as changing IP addresses or routing configurations.