Finding technology behind webapps using WhatWeb

There is no point starting a pentest against a web application without knowing what the actual technology is behind it. For example, it would be absolutely useless to run dirs3arch to look for files with the extension PHP when the technology is actually Asp. So, in this recipe, we will learn how to use a simple tool, WhatWeb, to reveal the technology behind a webapp. It comes by default in Kali.