This chapter describes in a step-by-step tutorial how to set up a fully-qualified mail server starting from sending a service SMTP using Postfix. We then started organizing the mail server, focusing on sending/receiving mail and virtual domains management via a secure database service MariaDB. Next, we learned about the mail reception service using POP3/IMAP using the MDA Dovecot with a medium level of security provided by the service itself. Then to start the extension part, which shows when the server can connect to an LDAP server and can gather useful information about the users and use them to send and receive mail. Finally, we finished off with a customized security level using OpenSSL to generate new certificate and keys to secure the service's authentication and encryption of the e-mails to be sent.
In the next chapter, we will learn how to set up and configure tools such as Nagios and syslog-ng on CentOS to monitor different services, and collect and process logs.