Which of the following is NOT a function of SMTP?

The function of SMTP, or Simple Mail Transfer Protocol, is primarily to manage the process of sending and transferring emails from one server to another or from a client to a server. It facilitates the transportation of email messages across networks, ensuring that they reach their intended recipients through a series of relays if necessary.

When considering the options provided, storing emails is not within the scope of what SMTP is designed to do. While email servers may store messages temporarily during the sending process, SMTP itself does not handle the storage of emails; that role falls to other protocols, such as IMAP (Internet Message Access Protocol) or POP3 (Post Office Protocol), which are specifically designed for email retrieval and storage.

Thus, the identification of storing emails as not being a function of SMTP reflects an understanding of the distinctive roles played by different protocols in the email communication system.