What Email Protocols (IMAP, POP3, SMTP) Are and How They Work

IMAP

IMAP (Internet Message Access Protocol) is a remote mailbox access protocol. It provides you with the comfort of accessing your mailbox from anywhere at the cost, that your mail needs to be stored on the server.

POP3

POP3 (Post Office Protocol 3) is a mail retreival protocol. You can use it to download mail from the mail server to your local computer. If you wish to use your mailbox from multiple locations, use of IMAP is recommended.

SMTP

SMTP (Simple Mail Transfer Protocol) is a protocol for sending mail. For it is not very resistant to spoofing, multiple technologies have been implemented to alleviate the problem.