What does a firewall primarily do?

A firewall primarily monitors and controls incoming and outgoing network traffic based on predetermined security rules. Its main function is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet. By doing so, it helps prevent unauthorized access to or from a private network. This is achieved through various methods, including packet filtering, where the firewall inspects packets of data and determines whether they should be allowed or blocked based on set security policies.

Firewalls can also function in various forms, such as hardware devices or software applications. They are essential components in network security because they help protect systems from attacks and unauthorized access by allowing only legitimate traffic and blocking suspicious or harmful data.

In contrast, while encryption involves securing data during transmission, backing up data protects against loss, and malware scanning focuses on identifying and removing malicious software, these functions are distinct from the primary role of a firewall in managing and controlling traffic.