In the context of network security, what is the primary function of a firewall?

The primary function of a firewall in the context of network security is to prevent unauthorized access to or from a network. Firewalls act as a barrier between trusted internal networks and untrusted external networks, such as the internet. They carefully monitor and control incoming and outgoing network traffic based on predetermined security rules. By analyzing data packets and blocking malicious traffic, a firewall helps protect sensitive information and resources from unwanted intrusions or attacks.

The other options pertain to different aspects of networking and server functions. Sharing resources over the network relates to how users and devices access files, printers, and applications. Optimizing network speed focuses on enhancing the performance and efficiency of data transmission between devices. Maintaining system time synchronization is associated with ensuring that all devices in a network operate on the same time standard, which is important for logging events and coordinating tasks. While these functions are important in their own right, they do not align with the specific role of a firewall in safeguarding network security.