Email: SMTP
Explore the Simple Mail Transfer Protocol (SMTP), its role in sending emails reliably using TCP, and the interaction between user agents and email servers. Understand SMTP's history, how emails are queued and transmitted, and common error handling scenarios. This lesson clarifies the push-based nature of SMTP and its partnership with receiving protocols like POP3 and IMAP.
We'll cover the following...
Introduction
Email has been a key application of the Internet since its early days.
Today, almost all formal or official correspondences occur on email. In fact, a lot of major corporations communicate primarily through email both externally and internally despite the advent of instant messaging.
Let’s see how this evergreen application really works!
SMTP
There are many protocols associated with email. One popular choice is a combination of POP3 and SMTP. One is used to send emails that are stored in a user’s inbox and the other is used to retrieve emails sent to you. However, the very core of electronic mail is the Simple Mail Transfer Protocol (SMTP).
SMTP uses TCP, which means that transfers are reliable. The connection is established at port 25.
Note: A good mnemonic to remember what SMTP does is Sending Mail To People. ...