You have initiated a scan of a remote host using an automated scanning tool. The tool reports that the host did not respond to an initial ICMP echo request, and thus the tool did not continue the scan because the host may not be reachable. Given the results of the scan, what BEST describes the status of the host?

You have initiated a scan of a remote host using an automated scanning tool. The tool reports that the host did not respond to an initial ICMP echo request, and thus the tool did not continue the scan because the host may not be reachable.

Given the results of the scan, what BEST describes the status of the host?

The host is offline and unreachable.

The host is online, but configured to block all incoming traffic for security purposes.

The host is online, but the scanning tool is improperly configured.

The host is online, but configured to not answer ICMP echo requests.

Explanation

The best description of the host is that the host is online, but configured to not answer ICMP echo requests, based on the scan result. In this scenario, you only know that the ICMP echo request did not receive a reply -- but not that host is blocking all traffic or is completely offline -- because you have not scanned using other protocols.

Consider that administrators configure some hosts to not answer ICMP echo requests; the hosts are still online and able to answer other traffic such as TCP, for example. Some scanning tools rely on ICMP echo request "probes" for host discovery, and will not scan an unresponsive host unless specifically told to.

Note that some tools such as nmap use multiple probes that include ICMP and TCP traffic to discover hosts by default, and include options to scan unresponsive hosts anyway.