GIAC Cybersecurity Technologies Practice Test 2025 – Complete Exam Prep

A firewall's primary function is to serve as a barrier between trusted internal networks and untrusted external networks, effectively protecting networks from unauthorized access. This involves monitoring and filtering incoming and outgoing network traffic based on predetermined security rules. By controlling access to and from a network, firewalls help to prevent unauthorized users or malicious software from exploiting vulnerabilities, thereby safeguarding sensitive data and resources.

While encryption is an important security measure, particularly for protecting data in transit, it is not the primary function of a firewall. Analyzing network traffic can be a feature of some firewalls, especially next-generation firewalls, but it is not their primary purpose. Storing user passwords is typically handled by authentication systems and databases, not firewalls. Thus, the focus of a firewall is distinctly on access control and prevention of unauthorized access, which underscores why this option is the most accurate representation of its primary role.