ACFE Certified Fraud Examiner (CFE) Financial Transactions and Fraud Schemes Practice Exam 2026 - Free CFE Practice Questions and Study Guide

The most accurate definition of a firewall is that it is a system that blocks unauthorized or unverified access to network assets by surveying incoming and outgoing transmissions. This definition captures the essential function of a firewall, which is to serve as a barrier between trusted internal networks and untrusted external networks, such as the internet. By inspecting data packets that are transmitted to and from a network, a firewall can determine whether those packets should be allowed through or blocked, thus protecting sensitive data and resources from potential threats.

Firewalls are critical components of network security, as they help to prevent unauthorized access and attacks by implementing specific rules and policies regarding traffic flow. They can be hardware-based, software-based, or a combination of both, and their effectiveness relies on robust configuration and ongoing management.

The other options do not reflect the primary purpose of a firewall. For example, the first option describes encryption rather than access control. The third option pertains to user authentication methods, such as biometric recognition, which is unrelated to the function of a firewall. Thus, the second option provides the most accurate and relevant definition, directly aligning with the role of a firewall in network security.