What is the primary function of a firewall?

The primary function of a firewall is to monitor and control incoming and outgoing network traffic. A firewall acts as a barrier between a trusted internal network and untrusted external networks, such as the internet. It analyzes the data packets traveling across this boundary and makes decisions about whether to allow or block them based on predetermined security rules.

By controlling traffic, firewalls can protect against unauthorized access to the network, preventing malicious activities such as hacking attempts, unauthorized data exfiltration, and denial-of-service attacks. Firewalls can be implemented in both hardware and software forms and are essential components of a robust network security strategy.

In comparison, the other options, such as encrypting sensitive data or storing backup copies, represent different aspects of security practices but do not encompass the primary purpose of a firewall. Similarly, while antivirus protection is crucial for cybersecurity, it operates on a different principle by detecting and removing malicious software rather than filtering and controlling network traffic.