|  |  | The Cisco Secure Scanner maps the network by scanning all IP addresses and port numbers specified in the configuration. The network discovery tool can accomplish the following: Scan entire networks, subnets, or single hosts. Profile systems. Discover type of system, e.g., router, firewall, workstation, server, hub. The scanner first pings every valid IP address within a pre-determined range to see which nodes answer. Because of this, you must allow Internet Control Message Protocol (ICMP) from the scanning hosts if doing a scan across a router.