Setting up your own mail server on Linux VPS is an important task for any Linux system administrator. Postfix is one of the most widely used and easiest mail server solutions available. It is a free, open-source, and powerful Mail Transfer Agent (MTA) that can be used to send and receive email. By default, Postfix is the default MTA software on all Linux distributions. Dovecot is an open-source IMAP and POP3 email server that can act as a mail storage server. It is used to deliver and retrieve emails to and from local mailboxes. Roundcube is a web-based IMAP email client that can read emails stored by Dovecot on virtual mailboxes. It provides all features you expect from an email client including MIME support, multiple sender identities, spell checking, folder manipulation, and many more. In this tutorial, we will show you how to set up a full-featured Mail server with Postfix, Dovecot and Roundcube on Ubuntu 20.04 VPS.