In the context of network security, what is a common purpose of a firewall?

A firewall is primarily employed to filter incoming and outgoing network traffic. Its main role is to enforce security policies by monitoring and controlling the traffic based on predefined rules. This involves allowing or blocking data packets based on various criteria, such as IP addresses, protocols, and port numbers. By regulating the flow of traffic, firewalls help prevent unauthorized access, protect sensitive information, and defend against cyber threats, making them a fundamental component of network security.

Other options do not align with the primary function of a firewall. While increasing internet speed, establishing network connections, and serving as a replacement for antivirus software involve different aspects of networking and security management, they are not the core responsibilities of a firewall. Firewalls are specifically designed to manage traffic and ensure secure communication, rather than influencing speed, establishing connections, or undertaking the role of antivirus programs.