Networking & Internet

SMTP

Definition

The Simple Mail Transfer Protocol (SMTP) is a communication protocol for electronic mail transmission. As its name indicates, SMTP is a push protocol and is used to send the e-mail, whereas POP3 or IMAP are used to retrieve it from the mail server.

Why It Matters

SMTP is the fundamental protocol for sending email across the internet. Every email you send is pushed from your email client to your mail server, and then from server to server, using SMTP.

Contextual Example

When you hit "Send" on an email, your email client connects to your provider's SMTP server (e.g., smtp.gmail.com) and uses the SMTP protocol to transfer the message.

Common Misunderstandings

  • SMTP is for sending email.
  • IMAP and POP3 are for receiving email.

Related Terms

Last Updated: December 17, 2025