Deep packet inspection (DPI) is a form of computer network packet filtering that examines the data part (and possibly also the header) of a packet as it passes an inspection point, searching for protocol non-compliance, viruses, spam, intrusions, or defined criteria to decide whether the packet may pass or if it needs to be routed to a different destination, or, for the purpose of collecting statistical information. It is a form of filtering employed at the security layer level of the OSI model. Stateful inspection, on the other hand, is a firewall technology that monitors the state of active connections and determines which network packets to allow through the firewall. Stateful inspection has largely replaced older technologies that were static and examined packets in isolation. Therefore, DPI is considered more secure because it examines the contents of the packets at Layer 7 (the application layer), while stateful inspection typically works up to Layer 4 (the transport layer).
Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS)

Defense-in-depth is a security strategy where multiple layers of defense are placed throughout an information technology (IT) system. It addresses physical, technical, and administrative controls to provide redundancy and ensure that if one layer fails, others will be in place to thwart an attack. References: Cisco Tech Roles - CyberOps Engineer

The average time taken by a Security Operations Center (SOC) to detect and resolve incidents is a critical metric for evaluating its effectiveness and scope. This metric reflects the SOC's efficiency in identifying security threats and its ability to respond and mitigate those threats promptly. It encompasses the entire incident lifecycle, from initial detection to final resolution, providing a comprehensive measure of the SOC's performance1.
References :=
* Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS)

A sandbox is a technology on a host that is used to isolate a running application from other applications. A sandbox creates a controlled and restricted environment for the application to execute, limiting its access to system resources and data. A sandbox can prevent the application from spreading malware, stealing information, or causing damage to the host or the network. A sandbox can also be used to test and analyze the behavior of unknown or suspicious applications without risking the security of the host. Application allow list, application block list, and host-based firewall are other technologies on a host that can be used to control or restrict the execution of applications, but they do not isolate them from other applications. References:
* How can I best isolate a particular program (game)
* App isolation in Windows 10
* Types of Endpoint Application Isolation and Containment Technology

tcpdump is an open-source packet capture tool that uses the libpcap library to capture network traffic on Linux and Mac OS X operating systems. It can display the contents of packets in various formats, filter packets based on criteria, and save packets to a file. tcpdump is a command-line tool that can be run on a terminal or a remote shell1 References: Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) - Module 2: Security Monitoring