Resara Server is an Active Directory compatible open source server for small businesses designed around Samba 4. It is designed to be simple and easy to use. Setup only takes a few minutes. The management console lets you manage users, share files, work with storage, and configure DHCP and DNS.
UCS is a reliable, pre-configured Linux server operating system featuring: Active Directory-like domain services compatible with Microsoft Active Directory; a mature and easy-to-use Web-based management system for user, rights, and infrastructure management; a scalable underlying concept suited for single server scenarios as well as to run and manage thousands of clients and servers for thousands of users within one single UCS domain; an app center providing single-click installation and integration of many business applications from 3rd parties and Univention; management capabilities to manage Linux- and UNIX-based clients; and command line, scripting interfaces, and APIs for automatization and extension. Its purpose is to provide Microsoft Server-like services on the cloud or on the premises, to run and operate corporate IT environments with Windows- and Linux-based clients, and to extend those environments with proven enterprise software.