What is POP3, SMTP, and IMAP?

Originating From: http://help.163.com/09/1223/14/5R7P6CJ600753VB8.html

POP3

POP3 is the abbreviation for post Office Protocol 3, the 3rd version of the Post Office Protocol, which specifies how to connect personal computers to the Internet's mail servers and electronic protocols for downloading e-mail. It is the first offline protocol standard for Internet e-mail, POP3 allows users to store messages from the server on a local host (that is, their own computer) while deleting messages saved on the mail server, while the POP3 server is the receiving mail server that follows the POP3 protocol to receive e-mail. (What is the difference from IMAP?) )

Smtp

The full name of SMTP is "Simple Mail Transfer Protocol", which is simply the message Transfer Protocol. It is a set of specifications for transferring messages from the source address to the destination, which controls how messages are relayed. The SMTP protocol is a TCP/IP protocol cluster that helps each computer find its next destination when sending or relaying letters. The SMTP server is the outgoing mail server that follows the SMTP protocol.
SMTP authentication, in short, requires that the account name and password must be provided before the SMTP server can be logged in, which makes it possible for spammers to have no opportunity.
The purpose of increasing SMTP authentication is to protect users from spam.

IMAP

The IMAP full name is Internet Mail Access Protocol, the interactive Mail Access Protocol, which is one of the standard protocols for mail access similar to POP3. The difference is that when IMAP is turned on, the messages you receive on the email client remain on the server, and the actions on the client are fed back to the server, such as deleting the message, marking the read, and so on, and the message on the server will also act accordingly. So whether you log in to the mailbox from the browser or the client software, you see the message and the status are consistent. (What is the difference from POP3?) ）

NetEase 163 Free Mailbox related server information:

NetEase Mailbox has been opened by default pop3/smtp/imap Service, so that you can better send and receive mail through the computer client software, if the shutdown can be opened by the following ways:

Please login 163 email, click " settings " directly above the page, and then click on the left "pop3/smtp/imap", where "turn on the SMTP service" is the system by default tick open. You can select the other two options in the diagram and click OK to open the success. Uncheck the two options in the diagram and click OK to close the success.  

What is POP3, SMTP, and IMAP?