Western Governors University (WGU) ICSC2211 D684 Introduction to Computer Science Practice Test

The protocol primarily used for sending emails is SMTP, which stands for Simple Mail Transfer Protocol. This protocol is designed specifically for the transmission of emails across networks. When a user sends an email, their email client uses SMTP to transfer the message to the mail server. From there, SMTP facilitates the forwarding of the email to the recipient's mail server.

SMTP operates over the Transmission Control Protocol (TCP) and typically uses port 25, although secure versions may use port 587. Its primary function is to send outgoing mail, making it essential for any email system.

In contrast, the other protocols mentioned serve different purposes in the email ecosystem. IMAP (Internet Message Access Protocol) is commonly used for retrieving emails, allowing users to access and manage their messages on the mail server without downloading them. POP3 (Post Office Protocol version 3) is also used for retrieving emails but typically downloads the email to the client and removes it from the server. HTTP (Hypertext Transfer Protocol) is primarily used for transferring web pages and is not directly related to email transmission.