"So you go to passport.com, which leads you to the Passport dev zone on MSDN, which leads you back to passport.com dev zone, which says the docs are in the SDK available from the MSDN downloads site. So you download a couple of megabytes of SDK setup file. And run it. To be told that you need to install it on a copy of NT Server. So you dig a little deeper into MSDN and it becomes obvious that Passport support on a website actually requires a set of ISAPI DLLs and is consequently tied completely to NT, 2000 or XP Server."
Just wondering, is NT a requirement to be able to run just the SDK, or the identification (production) server as well?
Update: "In the appendix at the back is a section on installing Passport support on non microsoft servers. It appears that somewhere there is a set of code that ends up as Apache .so, CGI and NSAPI code for Solaris, Red Hat Linux, FreeBSD and HP-UX."
03/24/02 update: Emerging Technology: Microsoft’s Passport to Controversy.