Abstract: A network appliance for scanning network nodes to determine open ports and vulnerabilities to attack by unauthorized users. A user initializes the system and method by remotely configuring the network scanner, initiating a new job by defining IP address ranges to be scanned, and iteratively assessing the vulnerabilities of assigned active network nodes. The vulnerability assessment comprises scanning all host network nodes within a user specified range of IP addresses, scanning all ports of host network nodes found to be active to determine open ports, and scanning all ports to assess vulnerabilities to unauthorized access using vulnerability scanner plug-ins. The vulnerability plug-in modules may be downloaded into a scanner on an “as required” basis. A user may access and configure the network scanner and define ranges of IP addresses to be protected from a remote client workstation.