In this article we will discuss how to work with SMTP (Simple Mail Transfer Protocol) and its protocols and how they work. We will show you how to define an SMtp mail server in Postfix, one of the most popular mail servers on the market today. In this tutorial you will learn how to configure a mail server that uses DKIM, Rspamd and MariaDB to securely transmit e-mails. You will be asked to select the type of configuration for post-fixing your mail server during the installation process. After sending an e-mail, the client sends a message to the contact and the mail server can start the "get-mail" conversation with him. The outgoing mail servers then need a way to transfer the e-mail either to the recipient or to the incoming mail server. You will contact the destination server for delivery and receive a contact. Hosting a mail server requires an MX entry that indicates the domain name of the mail transfer agent. The mail servers extract the domain name and e-mail address and...