What is the purpose of a "firewall"?

The purpose of a firewall is to monitor and control network traffic. Firewalls act as a barrier between trusted internal networks and untrusted external networks, such as the internet. They analyze incoming and outgoing traffic based on predetermined security rules, allowing or blocking specific traffic to protect the network from unauthorized access, malware, and other security threats. By filtering traffic, firewalls can prevent harmful data packets from entering a network, ensuring that only legitimate communications occur.

In contrast, the other options describe different functions that are not aligned with what firewalls do. Converting sensitive data into code pertains to encryption, which secures data rather than controlling network traffic. Delivering computing services over the internet refers to cloud computing, which provides services rather than monitoring network security. Exploiting vulnerabilities involves malicious activity aimed at breaching security, whereas firewalls are designed to enhance security and protect from such exploits.