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

The primary purpose of a firewall in network security is to monitor and control incoming and outgoing network traffic based on predetermined security rules. Firewalls act as a barrier between a trusted internal network and untrusted external networks, such as the internet. By examining packets of data transmitted over a network, firewalls can determine whether to allow or block traffic based on criteria such as IP addresses, protocols, and port numbers. This capability helps to prevent unauthorized access, cyber attacks, and data breaches, making it an essential component in establishing a secure network environment.

In contrast, the other choices highlight functions that do not align with the core purpose of a firewall. For example, encrypting confidential information is a function more closely associated with encryption tools, whereas firewalls primarily focus on managing traffic rather than safeguarding data content. Providing an unfiltered internet connection contradicts the firewall's purpose of regulating traffic, as it would expose the network to potential threats. Lastly, while a firewall can indirectly contribute to network performance by blocking harmful traffic, boosting speed and performance is not its main role; that is typically managed by network devices such as routers and switches.