What protocol is typically used for sending email?

The Simple Mail Transfer Protocol (SMTP) is the standard protocol used for sending email across the internet. It operates on a client-server model where the email client sends messages to the email server using SMTP commands. SMTP is designed specifically for the task of sending emails, enabling the transfer of messages from senders to recipients effectively.

In contrast, protocols like POP3 and IMAP4 are primarily focused on retrieving and managing emails at the recipient's end. POP3 allows users to download emails to their local devices, while IMAP4 provides a more synchronized experience, allowing multiple devices to access the same email account with messages stored on the server. Meanwhile, FTP is unrelated to email and is primarily used for transferring files between systems over the internet.

Understanding the roles of these protocols highlights why SMTP is the correct choice for sending email, as it is specifically designed for the sending and transferring of email messages.