Simple Main Transfer Protocol Used for sending email by authentication and directs transfer of email. Uses port 25 for plaintext and 587 for encrypted text
SMTP stands for Simple Mail Transfer Protocol. SMTP is a set of communication guidelines that allow software to transmit an electronic mail over the internet is called Simple Mail Transfer Protocol. It is a program used for sending messages to other computer users based on e-mail addresses.
SMTP is used twice to transfer main from client’s user agent to client’s server and then from client’s server to other person’s server.
SMTP sends email to sender’s receiving SMTP server. Then it is sent to receiver’s [[Protocols/POP3]] or [[Protocols/IMAP]] server and downloaded to receiver’s device.