Which protocol is used for sending emails?

Concept

In electronic mail, protocols are separated by function: message-transfer protocols submit and relay outgoing mail, while mail-access protocols retrieve or synchronize messages already stored in a mailbox.

The correct choice therefore depends on whether the task is sending or relaying mail, accessing a mailbox, or transferring general files.

Application

The stem asks specifically about sending email. SMTP stands for Simple Mail Transfer Protocol and is used to submit outgoing mail and relay messages between mail servers.

Contrast

• POP retrieves mail from a mailbox server, commonly by downloading it to a client.

• IMAP keeps mail on the server and synchronizes mailbox state across clients.

• FTP transfers general files between networked hosts; it is not an email transport protocol.

Cross-check

Separating transfer from access gives the same result: SMTP handles outgoing message transfer, whereas POP and IMAP handle mailbox access.

Result

Therefore, the protocol used for sending emails is SMTP.