sahirh asks: "I work as a penetration tester and recently started writing a whitepaper on the benefits of free, open-source security tools over commercial tools. Through my own experiences, I've found that many free tools such as Nessus and Kismet are more reliable and have better features than expensive commercial alternatives like ISS Internet Scanner or Airopeek. I've also noticed that tools like Ettercap have no commercial alternative. Further, the flexibility offered by the open-source nature of such tools is a great benefit. I'd like to ask for Slashdot's experiences and opinions on why you don't need to spend thousands of dollars on an expensive tool to perform a professional security assessment." Update: 02/07 11:15pm EDT by C : Thanks to all who wrote in to let us know the proper URL to the Kismet site.