What is the primary protocol used for email transmission?

The primary protocol used for email transmission is SMTP, which stands for Simple Mail Transfer Protocol. This protocol is specifically designed for sending and relaying outgoing emails from the sender’s email client to the recipient's mail server. SMTP operates using a set of rules and commands, ensuring that messages are properly transmitted across the internet.

When an email is sent, it is typically transmitted via SMTP to the email server for processing and eventual delivery to the recipient. This protocol effectively manages the routing of the email from the sender to the recipient's server.

While other protocols like IMAP (Internet Message Access Protocol) and POP3 (Post Office Protocol) are crucial for retrieving and storing email on the client side, their primary functions do not involve the initial sending of emails. IMAP allows users to manage and synchronize their email across multiple devices, while POP3 is primarily used to download emails from the server to a local device and often prevents emails from being stored on the server afterward. HTTP (Hypertext Transfer Protocol) is primarily used for transferring web pages and not for email transmission.