What does SMTP mean? It is short for Simple Mail Transfer Protocol and defines the method that handles the process of transaction and transfer of email over IP.

Simply put, when you send a message to a friend using a mail client, it is chosen by an outgoing server (called an SMTP server) that initiates a conversation with your friend's inbound.

During this process, the machines "talk" SMTP: the protocol provides a set of standard and certain guidelines for servers to recognize and communicate to understand who the sender is, who the recipient is, where the content should go, and so on.