Windows Home Server is a Servers & Network software developed by Microsoft. After our trial and test, the software is proved to be official, secure and free. Here is the official description for Windows Home Server:

Marydown Editor: Windows Home Server 2011 helps multi-PC families easily centralize, connect, and personalize their digital files. It provides a simple, familiar, and reliable way to store, stream, share and automatically protect what is most important.

A more robust system
Windows Home Server 2011 is based on Windows Server® 2008 R2, the most secure and powerful Windows server to date. In addition, we’ve made the system more robust by adding the following features:
• The ability to use best-of-breed 64-bit product technologies—perfect for powering the media-heavy home.
• A Standard Development Kit (SDK) with client-side software deployment for easy customization and deployment
• DLNA 1.5 compliance to ensure that all your home electronic devices work with your Windows Server-based network.

Easier installation
We designed Windows Home Server 2011 to be easier than ever to install. With the following features, your home server can be up and running within minutes, even if you have limited technical experience.
• A simplified setup experience with detailed guidance for configuring the server and each connected PCs.
• A new option to install Windows Home Server clients through a web PaGE (instead of using physical media or a share)
• The ability to let users set up their own PC—without the need for an administrator
• A fully customizable home page
• Out of the box-support for Mac/Apple clients, with full access to standard Windows Home Server administrative functions.
• Support for HomeGroup, a new feature in Windows 7 that makes it easy for PCs and devices to connect with each other.

Simpler management
From a centralized management Dashboard to user alerts and warnings, Windows Home Server 2011 helps take the hassle out of managing a network. We’ve made several improvements to make managing your home server simpler than ever before. And more...