What role does a firewall play in network security?

A firewall is a crucial component of network security as it monitors and controls incoming and outgoing network traffic based on predetermined security rules. Its primary function is to create a barrier between trusted internal networks and untrusted external networks, such as the internet. This helps to prevent unauthorized access and protect sensitive data from potential attacks.

By inspecting traffic and blocking or allowing data packets according to specific security policies, a firewall helps ensure that malicious traffic does not compromise the internal network. This monitoring capability enables organizations to track potential threats and respond to them effectively, contributing significantly to the overall security posture of a network.

In contrast, the other options suggest functions that either do not align with the primary purpose of a firewall or are unrelated to its security role. Boosting network speed is typically not a direct result of having a firewall; facilitating user access to unauthorized sites goes against the core protective function of a firewall; and while data storage may relate to data management, it does not describe the essential duties of a firewall in protecting network integrity.