Which protocol is used for sending email over the internet?

The protocol used for sending email over the internet is Simple Mail Transfer Protocol, commonly abbreviated as SMTP. This protocol is specifically designed for transferring emails from a sender’s device to a receiving mail server and for relaying outgoing mail between servers. It operates at the application layer of the Internet Protocol Suite and is responsible for ensuring email is delivered correctly and efficiently across various networks.

In contrast, HTTP and HTTPS are protocols primarily used for web browsing, where HTTP is the standard protocol for transmitting web pages and HTTPS is the secure version that encrypts data during transmission. FTP, or File Transfer Protocol, is used for transferring files between computers on a network, which does not pertain to email transmission. Understanding the specific functions of these protocols highlights why SMTP is the only correct choice for email sending.