How does a firewall enhance network security?

A firewall enhances network security primarily by controlling data access based on security rules. This function is crucial for protecting a network from unauthorized access and potential threats. Firewalls act as a barrier between a trusted internal network and untrusted external entities, filtering incoming and outgoing traffic according to predefined security policies. By establishing these rules, a firewall can determine which data packets are allowed through and which should be blocked, effectively reducing the risk of security breaches.

For instance, a firewall can be configured to permit only specific types of traffic, such as HTTP or HTTPS for web browsing, while blocking all other forms of communication that could pose a risk. This selective control helps ensure that only legitimate and safe traffic can interact with the network, significantly bolstering overall security.

Other options listed do not align with the primary function of a firewall. While optimizing data flow can contribute to network performance, it does not directly enhance security. Managing software updates is essential for maintaining security on devices but is not a core function of a firewall. Compressing files is related to storage efficiency and data transfer speed rather than network security.