Wrote my thesis about passive and active fingerprinting, it's very easy to do, most operating systems network stacks have different default values like window s

Wrote my thesis about passive and active fingerprinting, it's very easy to do, most operating systems network stacks have different default values like window size, ttl etc. p0f[1] was pretty good back then. http://lcamtuf.coredump.cx/p0f3/ http://lcamtuf.coredump.cx/p0f3/