What is the primary function of a firewall in network security?

The primary function of a firewall in network security is to monitor and control network traffic based on predefined security rules. Firewalls act as a barrier between trusted internal networks and untrusted external networks, such as the internet. They evaluate incoming and outgoing traffic, allowing or blocking data packets based on established security policies.

By doing this, firewalls protect networks from unauthorized access and various cyber threats, like intrusions or malware. They can be configured to allow traffic that meets specific security criteria while denying all other traffic, thus helping to maintain the integrity and security of the network.

In contrast, the other options describe functions that are not directly related to the core purpose of a firewall. For instance, creating a backup of data is a function typically associated with data management solutions rather than network security. Providing internet connectivity involves networking equipment such as routers and modems, and managing user accounts pertains to identity and access management systems. These roles are distinct from the primary function of a firewall, which is focused solely on traffic control and monitoring.