Abstract: Disclosed is a method of and apparatus for ascertaining system vulnerabilities of shareable devices, such as servers in a network, starting with only a list of all assigned addresses used by the system. A query is sent consecutively to each address on the list. Those addresses from which a response is not received are filtered from the list and used to generate an “unused” list. By checking the response received from the remaining addresses, non shareable devices may be ascertained and likewise filtered from the list while being used to generate a “non shareable” list. The remaining addresses thus all relate to shareable devices which can then be efficiently scanned for system vulnerabilities and a report generated as to data revealed when a report is desired.