What functionality does a firewall provide in a network?

A firewall primarily serves to provide external network protection by monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet. The primary aim of a firewall is to prevent unauthorized access to or from a private network, thereby protecting sensitive information and resources from potential security threats.

Firewalls can help mitigate risks from various cyber threats, including hackers and malware, thus maintaining the integrity, confidentiality, and availability of the network's data. They accomplish this by inspecting data packets and making decisions to allow or block traffic based on defined security policies, which may include factors like IP addresses, port numbers, and protocols.

Understanding the primary role of a firewall as a protective measure for the network helps emphasize its importance in maintaining a secure computing environment.