GFI LANguard is a tool I found as a useful replacement for Nessus (BackTrack does not include Nessus). It is only free with this BackTrack distribution. I found this tool to be a slightly slimmed down version of Nessus. On the other hand it was incredibly easy to use and it provides a wealth of information. It can scan a range of IPs to determine open ports, operating systems, common vulnerabilities, users, shares, running processes, security policies, missing patches, SNMP devices and functions they provide. This demo shows a limited use of its features and the results are more glorious on a larger network.