What does a firewall primarily do?

A firewall primarily monitors and controls incoming and outgoing network traffic based on predefined security rules. Its main purpose is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet. By inspecting data packets passing through it, a firewall can determine whether to allow or block specific traffic based on the set rules, contributing to the protection of the network from unauthorized access and potential threats.

The functionality of a firewall is critical for maintaining the security posture of a network, enabling it to defend against intrusions, malware, and various forms of cyberattacks. This role is distinct from those of other tools and practices, which focus on different aspects of network management, such as data backup or user account management.