p0f

Versatile passive OS fingerprinting, masquerade detection tool
http://lcamtuf.coredump.cx/p0f3/

Current version
3.09b

Recent formula history

Alex Dunn p0f 3.09b
Tomasz Pajor p0f 3.08b
Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Jack Nagel Provide a method to access test fixtures
Mike McQuaid p0f: use existing pcap fixture for test.

Formula code at GitHub