What is a "firewall" used for?

A firewall is fundamentally a network device designed to monitor and control incoming and outgoing network traffic based on predetermined security rules. Its primary function is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet. By doing this, firewalls help protect networks from various types of threats, including unauthorized access, malware, and other cyberattacks.

Firewalls achieve this control by filtering traffic according to specific protocols and port information, which can be configured to allow or deny data packets as per the organization's security policies. This capability is essential for maintaining the integrity and security of sensitive data and systems within the network. Firewalls can be implemented as hardware devices, software applications, or a combination of both, making them versatile tools in cybersecurity strategies.

Other options such as enhancing software performance, encrypting data, or automating tasks do not accurately define the primary purpose of a firewall. These activities involve different types of tools and technologies that serve distinct functions within the realm of cybersecurity and IT management.