Which security measure is typically implemented to prevent unauthorized access to a network?

A firewall is a crucial security measure designed to prevent unauthorized access to a network. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet. By filtering incoming and outgoing traffic based on predetermined security rules, firewalls help protect sensitive data and critical infrastructure from external threats and unauthorized users.

Firewalls can be hardware-based, software-based, or a combination of both, and they are essential for maintaining the integrity and security of the network. They can block malicious activities, such as hacking attempts and certain types of malware, by restricting access to only legitimate traffic. This makes them a primary line of defense in network security strategies.

While other security measures like antivirus software, password protection, and encryption are also important, they serve different specific purposes. Antivirus software focuses on detecting and eliminating malware, password protection controls access to individual accounts, and encryption secures data in transit or at rest. None of these directly provide the perimeter security that a firewall does, highlighting its central role in preventing unauthorized network access.