I m sure the 9x and NT4 2000 stack was not rewritten maybe only partially contrary to what said the former employer but I admit I have no valid external documentation link to point for this was my personal experience with wireshark and protocol packets confirmed in BSD article Most of the rewriting happened between XP and Vista so NT5 1 anyway post 2000 XP sometimes still show an old ARP bug About command line tools why you remove the sentence and not modified accordingly Anyway I understood your point about BSD vs FreeBSD