Xprobe is an alternative to some tools which are heavily dependent upon the
usage of the TCP protocol for remote active operating system fingerprinting.
Xprobe I combines 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 an 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 matches simultaneously, and a
signature database.