Cisco Defense Orchestrator (CDO) is the tool that assists engineers in performing an audit of network projects to determine which objects are duplicated across various firewall models, including Cisco Secure Firewall Threat Defense, Cisco Secure Firewall ASA, and Meraki MX Series. CDO provides a unified management interface for managing multiple security devices and can identify duplicate objects across these devices. Steps: * Access Cisco Defense Orchestrator. * Connect and synchronize all relevant firewall devices (FTD, ASA, Meraki MX). * Use the audit and reporting features in CDO to identify and manage duplicate objects. This helps ensure consistency and efficient management across the organization's firewall deployments. References: Cisco Defense Orchestrator Documentation, Chapter on Device Management and Object Auditing.