What is the role of a firewall in network security?

A firewall plays a crucial role in network security primarily by monitoring and controlling incoming and outgoing traffic based on predetermined security rules. Its main function is to create a barrier between trusted internal networks and untrusted external networks, effectively filtering traffic to prevent unauthorized access and protect sensitive data. By allowing or blocking traffic according to security configurations, firewalls help to mitigate threats such as unauthorized access attempts, intrusion, or data exfiltration.

The other options describe functions that are not the primary role of a firewall. Enhancing Wi-Fi signal strength relates to optimizing network connectivity rather than security. Performing regular data backups is vital for data recovery but does not involve traffic control. Scanning for malware and viruses is typically handled by dedicated security software, such as antivirus programs, which are focused on detecting malicious software rather than regulating network traffic.

Thus, the option that correctly identifies the core function of a firewall is its ability to monitor and control network traffic, establishing it as a critical component of an organization's cybersecurity posture.