Get the Whitepaper called Bluffing Network Scan Tools – What You See May Not Be What You Get. This is a little paper to remind people that results from automatic tools are always interpretations of incoming data. Tools expect a certain behaviour from systems, and will make some assumptions. If you do not know this, you may be fooled by false positives or worse loose your valuable time.
You can download it from the following link: https://packetstormsecurity.com/files/download/134657/BluffNetworkScanTools.pdf
Source: https://packetstormsecurity.com/files/134657/Bluffing-Network-Scan-Tools.html