What is the purpose of Simple Mail Transfer Protocol (SMTP)?

The primary purpose of Simple Mail Transfer Protocol (SMTP) is to facilitate the sending of email messages between servers. SMTP functions as a protocol used to transfer email data from one server to another, guiding the route that the message takes until it reaches its destination. This is a crucial step in the email delivery process, as it ensures that messages are delivered from the sender's email server to the recipient's email server.

While it's true that other protocols handle different aspects of email communication—such as retrieving emails or storing them—SMTP's specific role is dedicated to the transfer aspect. For example, protocols like IMAP and POP3 are responsible for retrieving and managing emails on the recipient's end, but they do not engage in the actual sending of messages. Thus, understanding SMTP as the protocol for sending emails clarifies its essential function in the overall framework of email communication.