Explanation
The most important thing for incident management to focus on when addressing an issue that causes an outage is restoring the system to operational state as quickly as possible. Incident management is the process of detecting, investigating, and resolving incidents that disrupt or degrade a service or system. An incident is an unplanned event that affects the normal functioning or quality of a service or system. An outage is a type of incident that causes a complete loss of service or system availability. The main goal of incident management is to restore the service or system to its operational state as quickly as possible, minimizing the impact on users and business operations.
*The other options are not as important as option B. Analyzing the root cause of the outage to ensure the incident will not re-occur is a valuable activity, but not the most important thing for incident management to focus on when addressing an issue that causes an outage. Root cause analysis is a process of identifying and eliminating the underlying factors that caused an incident or problem. Root cause analysis can help to prevent or reduce the likelihood of similar incidents or problems in the future. However, root cause analysis is usually performed after the incident has been resolved and the service or system has been restored. Ensuring all resolution steps are fully documented prior to returning the system to service is a good practice, but not the most important thing for incident management to focus on when addressing an issue that causes an outage.
Documentation is a process of recording and maintaining information about an incident and its resolution steps. Documentation can help to improve communication, accountability, learning, and improvement within incident management. However, documentation should not delay or interfere with the restoration of the service or system. Rolling back the unsuccessful change to the previous state is a possible solution, but not the most important thing for incident management to focus on when addressing an issue that causes an outage. Rolling back is a process of reverting a change that has been applied to a service or system that caused an incident or problem. Rolling back can help to restore the service or system to its previous state before the change was made.

Traffic for the internal network that did not originate from the mail gateway is a sign that firewall-1 is not functioning properly. This may have been be caused by an attack from a hacker. Closing firewa!l-2 is the first thing that should be done, thus preventing damage to the internal network. After closing firewall-2, the malfunctioning of firewall-1 can be investigated. The IDS should trigger the closing of firewall-2 either automatically or by manual intervention. Between the detection by the IDS and a response from the system administrator valuable time can be lost, in which a hacker could also compromise firewall-2. An entry in the log is valuable for later analysis, but before that, the IDS should close firewall-2. If firewall-1 has already been compromised by a hacker, it might not be possible for the IDS to close it.