"While Microsoft did technically 'buy' their TCP/IP stack from Spider Systems, they did not "own" it. Spider used the code available and written for BSD, so it doesn't appear that Microsoft directly copied BSD code (which, again, it is perfectly legal and legitimate to copy), they got it from a third party. Also ftp, rcp and rsh seems to have come with the bundle. I have heard that ftp was, but have never used rcp and rsh on Windows, so don't know what version(s) those were or were not included in any particular Windows version. Anyone can look through the .exes for those files and look for "The Regents of the University of California" copyright notice, if they want to see for themselves (rather than take the word of some anonymous geeks on a forum) ;)"
[1] Windows TCPIP Stack Based on Unix ?
https://www.neowin.net/forum/topic/381190-windows-tcpip-stac...