Courier-imap is an enterprise IMAP server which is fast, scalable and that allows you to use Maildirs.
Courier-imap can easily manage hundreds of thousands email accounts.
Then, Double Precision (the author of Courier) also provides the SSL support for IMAP with its "courier-imap-ssl" package.
Courier-pop provides the POP3 protocol that allows your users to check emails with an email client such as Microsoft Outlook, Mozilla ThunderBird or the client installed on their smartphone.
Postfix is the most known mail server in the Linux world, but its complexity also makes it complicated to configure at first time.
Postfixadmin is a Web interface written in PHP that allows you to create and manage email addresses of your personal email server.
With this web interface, you can define your virtual domains, create your own email addresses on your mail server (postfix), and more.
RoundCube Webmail is a complete professional webmail and it is the most used webmail servers on Linux.
Moreover, he is proposed by most known web hosts.
5 software displayed.