What is SMTP?
SMTP stands for Simple Mail Transfer Protocol, a standard set of rules for sending email through the internet. At the user level, it is generally used only as a sending protocol. For receiving, applications generally prefer other protocols like POP3 or IMAP.
How does SMTP work?
While not used by employed by user-level email clients, SMTP is often utilized by email servers and mail transfer agents.
SMTP connections can be secured by SSL, known as SMTPS.