What is the purpose of a firewall?

A firewall serves a critical role in network security by filtering and monitoring traffic that enters and leaves a network. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet. By enforcing a set of predetermined security rules, a firewall allows only authorized traffic to pass through while blocking potentially harmful or unauthorized access attempts.

This functionality helps to protect sensitive data, prevent unauthorized access to network resources, and mitigate various types of attacks, including malware infections and denial-of-service attacks. Firewalls can employ various techniques, such as packet filtering, stateful inspection, and proxy services, to analyze the traffic based on IP addresses, port numbers, and protocols.

The other options pertain to different aspects of IT and security management but do not align directly with the fundamental role of a firewall in network protection. For example, providing software updates is essential for keeping systems secure but relates to patch management rather than traffic management. Ensuring data integrity involves safeguarding data from unauthorized alteration, which is a different security concern. Managing user access levels pertains to identity and access management, focusing on who can access certain resources rather than monitoring traffic flow.