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

The primary purpose of a firewall in network security is to prevent unauthorized access to or from the network. Firewalls act as a barrier between trusted internal networks and untrusted external networks, such as the internet. They enforce security policies by examining incoming and outgoing traffic and controlling access based on a set of predetermined rules.

By determining which traffic should be allowed and which should be blocked, firewalls help protect sensitive data and resources from malicious activities, such as hacking and intrusion attempts. This primary function is crucial for maintaining the security and integrity of both the network and connected devices.

While the other choices touch on important aspects of network operations and security, they do not capture the core purpose of a firewall. User authentication is related to who can access the network, monitoring and logging traffic is important for understanding network activity, and optimizing network performance focuses on efficiency and speed. However, these functions do not define the main role of a firewall, which is fundamentally about controlling access to ensure a secure network environment.