The correct answer is B. The rule set was configured to allow specific IP addresses. CompTIA DataSys+ materials emphasize the importance of network security controls, particularly firewall rules and access control lists (ACLs), in regulating remote database access. In this scenario, the database server is reachable by users in Brazil but not by users in Canada, which strongly indicates that access is being selectively permitted rather than globally blocked.
Firewall rule sets are often configured using IP-based allowlists, where only approved IP addresses or IP ranges are permitted to establish a connection. If the analyst allowed the IP address range associated with Brazil but did not include the IP range used by Canadian users, connections from Canada would fail while Brazilian users would still have access. This behavior aligns precisely with selective rule-based access control, a common best practice highlighted in DataSys+ for reducing attack surfaces.
Option A is incorrect because if the perimeter network were rejecting remote connections entirely, users in Brazil would also be unable to connect. Option C is incorrect for the same reason: a firewall rule denying all connections would block access from all locations, not just Canada. Option D, server port security being disabled, would typically prevent all inbound connections to the database service, again affecting all users regardless of geography.
CompTIA DataSys+ stresses that troubleshooting connectivity issues requires identifying whether failures are global or location-specific. Location-specific failures are most commonly caused by misconfigured firewall rules, IP filtering, or regional access restrictions. In database environments that support remote access, DBAs must ensure that firewall rules are consistently applied to all authorized networks.
Therefore, the most accurate and verified explanation is that the rule set was configured to allow specific IP addresses, and the Canadian users’ IP range was not included. This makes option B the correct answer.
