Active Server Page, or ASP, is a Microsoft language. So, the most common answer is Windows. Linux will support some versions of the ASP language, but there are better alternatives for Linux, such as PHP.
Windows 2003 Server is the Best
Active Directory was previewed in 1999, released first with Windows 2000 Server edition
You will need a Active Domain Server (e.g. a computer running Windows Server as the operating system) as far as I remember.
A server operating system is an operating system that is designed to run on servers. Some of the operating systems include; Windows, Mac OS, and Linux.
Nothing
Active Directory
Yes. Fedora is often used as, and is fully capable of, serving as a server operating system.
Server virtualization is the partitioning of a single of a single server each of which can support a different operating system.
iOS is not a server. It is an operating system made by Apple.
Many operating systems are used on servers, including Linux, Windows Server, Solaris, FreeBSD, and Mac OS X Server.
An operating system which is run on server but is assessed/interacted with by a terminal.
Netware