In this tutorial, we will examine the process of installing Zimbra mail server in CentOS Linux environment. Zimbra is my personal favorite when it comes to open-source mail servers as it comes with a number of useful features such as built-in calendar support, email filtering rules, a modern interface for both users and admins, spam and malware scanners, etc. Besides server-side components, Zimbra also boasts of a full-featured web-based email client.