CompTIA Cloud+ Complete Practice Test 2025

The inability to reach a web server after provisioning multiple virtual machines behind NAT can often be attributed to the configuration of a firewall. A firewall serves as a security barrier that monitors and controls incoming and outgoing network traffic based on predetermined security rules. When multiple virtual machines are deployed behind NAT, the firewall may restrict access to certain ports or services.

In this scenario, if the firewall is set to block HTTP or HTTPS traffic, or if it isn't configured to allow forwarded connections to the web server, users outside the NAT network will be unable to reach the server, resulting in connectivity issues. Proper firewall rules need to be established to ensure that requests can properly pass through to the web server, enabling access as intended.

While other options like IPS (Intrusion Prevention System) and IDS (Intrusion Detection System) play roles in network security, they typically focus on monitoring and responding to potential threats rather than controlling access directly. Blacklisting may block specific IPs or domains but does not inherently affect access to a web server unless those items are explicitly listed. Thus, the firewall is the most likely culprit in this scenario.