NethServer is an all-in-one Linux distribution based on CentOS, which is the clone of popular commercial Linux distribution Red hat Enterprise Linux. It ships with powerful, yet easy to use web interface that enables us to install plenty of pre-configured modules with a single mouse click. It is completely free, and 100% open source distribution supported by many contributors and community members all over the world. NethServer is opt for small office and medium enterprise organizations, and of course you can use it for large enterprises if you have sufficient high-end configuration system.