What is the role of a firewall in an operating system?

A firewall plays a crucial role in an operating system by filtering network traffic based on security rules. Its primary function is to establish a barrier between a trusted internal network and untrusted external networks, such as the Internet. By doing this, a firewall helps protect the system from unauthorized access and potential threats, such as malware or hackers trying to penetrate the network.

Firewalls can be configured to allow or block specific types of traffic based on defined security policies. This includes rules about which ports are open for communication, which IP addresses are permitted to connect, and what types of protocols can be used. By filtering this traffic, firewalls help maintain the integrity and confidentiality of the data by ensuring that only legitimate traffic is allowed in and out of the network.

The other choices, while related to computer systems and their operations, do not accurately capture the primary function of a firewall. Monitoring user activity focuses more on tracking and logging user actions rather than filtering network communications. Enhancing software performance relates to optimizing how applications run, which is not the purpose of a firewall. Allocating system resources involves managing CPU, memory, and storage, which are distinct from the security-centric role of a firewall.