Virtual Server is a Microsoft Windows-based server application that is optimized to provide virtualization of Windows Server operating systems concurrently on a single physical server. In combination with the Windows Server 2003 operating system, Virtual Server provides a platform for implementing domain controllers in virtual...
Virtualization
As far as I know, the only Mac software that Microsoft offers to MSDN subscribers is Virtual PC for Mac. The latest version available through MSDN is 7.0.1 and is.
You may know that loopback is used for testing, or debugging system problems by sending the data out and then delivering back to the source without actually sending it across.