What is the difference between POP and SMTP protocol? - Quora
Outlook365: IMAP, POP3, and SMTP settings | Blog | Limilabs
Lecture 4/12/2006 Basic Steps of Email Transaction A sender sends an e-mail to a recepient through a re-laying SMTP server. The recepient gets the e-mail from the receiving SMTP server either through IMAP, POP3 or a shared file system. Any combination ...