SOGo is a fully supported and trusted groupware server with a focus on scalability and open standards.
In computing, a server is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called "clients". This architecture is called the client–server model. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client.
Plesk is a commercial web hosting platform with a control panel that allows a server administrator to set up new websites, reseller accounts, e-mail accounts and DNS entries through a web-based interface.
It is a self-hosted monitoring tool like "Uptime Robot".
osTicket is a widely-used open source support ticket system.