Written and maintained by Fyodor Yarochkin, Meder Kydyraliev and Ofir Arkin, Xprobe (I & II) is an active OS fingerprinting tools based on Ofir Arkin’s ICMP Usage In Scanning Research project.Xprobe is an alternative to some tools which are heavily dependent upon the usage of the TCP protocol for remote active operating system fingerprinting. The first version of Xprobe2 combined various remote active operating system fingerprinting methods using the ICMP protocol, which were discovered during the “ICMP Usage in Scanning” research project, into a simple, fast, efficient and a powerful way to detect the underlying operating system a targeted host is using. Xprobe2 is an active operating system fingerprinting tool with a different approach to operating system fingerprinting. Xprobe2 rely on fuzzy signature matching, probabilistic guesses, multiple simultaneously matches, and a signature database.