HOWTO: Synchronize app passwords with a Windows domain

You may want to know how to make your PHP app on a Unix, Linux, or
Windows host synch up with a Windows domain. It's simple. Just start
an IIS server, then secure it to the nine yards with the security
patches and advice from the Microsoft website. (Have fun doing that,
by the way! Tee hee.) Next, you create a page on that IIS host that
simply returns the phrase, "OKAY". Next, secure just that page with
Basic and Windows NT C/R IIS security to the domain you wish, choosing
"Domain Users". Next, from PHP on another web host (IIS, Apache,
whatever), use the cURL functions (or socket library) to hit that web
page and return the result. If it returns "OKAY", then the user's
username and password are correct. If you get an error, then the
username and/or password are incorrect for that domain.