| NetSonar is a Cisco product that is used to both map out hosts on networks and search them for vulnerabilities. Based on the premise of Dan Farmer's white paper, "How to Improve The Security of Your Site By Breaking Into It," NetSonar can analyze the security of a perimeter network, DMZ, firewall, or internal network. Cisco recommends you regularly run a vulnerability detection tool like NetSonar to search for new hosts and vulnerabilities.