What role does a firewall play in a network?

A firewall acts as a crucial security measure within a network by preventing unauthorized access to or from that network. It establishes a barrier between trusted internal networks and untrusted external networks, such as the internet. By analyzing incoming and outgoing traffic based on predetermined security rules, a firewall can block harmful traffic, thus protecting sensitive data and resources from unauthorized access or attacks.

This function is essential for maintaining the confidentiality, integrity, and availability of the network’s information. Furthermore, firewalls can be configured to allow or deny specific traffic, thereby enforcing policies that align with the organization's security requirements. As cyber threats continue to evolve, the role of firewalls becomes increasingly significant, reinforcing the need for robust network security protocols.

The other options fail to capture the primary function of a firewall. While a firewall may log traffic, this is a secondary feature rather than its main purpose. Similarly, connecting networks or improving internet speeds does not align with the fundamental role of a firewall, which is strictly focused on security.