A private server is a machine or virtual machine that is privately administrated. As servers need adequate internet connection, power and can be noisy, they are often located in a colocation center. Servers are available on the market the same way as laptops or desktops are available and can be purchased by individual already pre-configured. Ordinary desktop computers are not suitable to house in colocation centers as servers have specific form factor that allows them to fit many into a standard rack. This group also includes custom-designed experimental servers, made by hobbyists Virtual server also offer high degree of freedom, superuser access and low-cost service.