Network Defense Essentials (NDE) Practice Exam 2025 - Free Network Defense Practice Questions and Study Guide

A firewall plays a crucial role in tracing incoming and outgoing traffic in a network by acting as a barrier between a trusted internal network and untrusted external networks, such as the internet. It monitors and controls the data packets that enter and exit the network, logging various attributes of the traffic in the process. This logging capability enables network administrators to analyze traffic patterns, identify unauthorized access attempts, and investigate potential security breaches.

Additionally, firewalls can be configured to enforce specific security policies, allowing or denying traffic based on predefined rules. By examining the traffic flows on a network, firewalls not only enhance security but also provide valuable data for network management and compliance audits.

In contrast, while other options may contribute to overall security, they do not primarily serve the function of tracing traffic. A VPN primarily focuses on providing secure, encrypted connections to users accessing the internet anonymously. Antivirus software is designed to detect and remove malware but does not track network traffic. Network mapping helps visualize the connections and layout of the network, but it doesn't monitor or control traffic in the same way a firewall does.