What function do firewalls serve in a network?

Firewalls play a crucial role in network security by filtering incoming and outgoing traffic based on predefined security rules. This function allows them to control the flow of data between networks, ensuring that only authorized traffic can pass through. By examining the packets of data that attempt to enter or exit a network, firewalls can block potentially harmful traffic, such as unauthorized access attempts, malware, or other malicious activities.

The ability to set specific rules means that organizations can customize their firewall configurations to meet their unique security needs, allowing them to permit or deny traffic based on various criteria, including IP addresses, port numbers, and application types. This proactive approach helps in creating a secure network environment, protecting sensitive data, and maintaining overall network integrity.

Other options do not accurately describe the primary function of a firewall. Creating backups or encrypting communications are entirely different processes that involve data storage and data protection, respectively, while monitoring employee productivity typically falls under network management and oversight rather than security.