What is ClearOS?
ClearOS is a family of operating systems for the enterprise, small business, and home. There are three editions to choose from depending on your needs and suitable to your abilities. They are: ClearOS Enterprise, ClearOS Home, and ClearOS Core.
ClearOS is a powerful network and gateway server designed for small organizations and distributed environments. Though ClearOS comes with an extensive list of features and integrated services, the solution is easy to configure thanks to the intuitive web-based interface.
Comments and Reviews
Said about ClearOS as an alternative
it is more robust than zentyal
The web interface is more intuitive and easier. and it has more features. Although it has not the option as Exchange server. But that is to me a minor thing. You can add that separately afterwards.
very easy to use and inexpensive