A firewall is a device or software that monitors and controls the incoming and outgoing network traffic based on predefined rules. A firewall can help protect an organization’s network and information systems from unauthorized or malicious access, by filtering or blocking unwanted or harmful packets. The most important thing for an IS auditor to verify when evaluating an organization’s firewall is that the logs are being collected in a separate protected host. Logs are records of events or activities that occur on a system or network, such as connections, requests, responses, errors, and alerts. Logs can provide valuable information for auditing, monitoring, troubleshooting, and investigating security incidents. However, logs can also be tampered with, deleted, or corrupted by attackers or insiders who want to hide their tracks or evidence of their actions. Therefore, it is essential that logs are stored in a separate host that is isolated and secured from the network and the firewall itself, to prevent unauthorized access or modification of the logs. Automated alerts are being sent when a risk is detected is a good practice for enhancing the security and efficiency of a firewall, but it is not the most important thing for an IS auditor to verify, as alerts may not always be accurate, timely, or actionable. Insider attacks are being controlled is a desirable outcome for a firewall, but it is not the most important thing for an IS auditor to verify, as insider attacks may involve other factors or methods that bypass or compromise the firewall, such as social engineering, credential theft, or physical access. Access to configuration files is restricted is a critical control for ensuring the security and integrity of a firewall, but it is not the most important thing for an IS auditor to verify, as configuration files may not reflect the actual state or performance of the firewall.