What is the purpose of a firewall?

The purpose of a firewall is primarily to prevent unauthorized access to computers and networks. Firewalls act as a security barrier between trusted internal networks and untrusted external networks, such as the internet. They filter incoming and outgoing traffic based on predetermined security rules. By doing so, they help protect sensitive data from cyber threats, viruses, and unauthorized users trying to gain access to the system.

While other options listed might include important functions in an office environment, they do not align with the key role of a firewall in cybersecurity. For instance, although enhancing user productivity is crucial in an office setting, it is not the primary function of a firewall. Similarly, backing up data and managing payroll systems pertain to other aspects of IT and office management but are unrelated to the security services that a firewall provides.