POP3, SMTP, and IMAP basic concepts

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.

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.

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What's the difference between IMAP and POP3?

The POP3 protocol allows e-mail clients to download messages on the server, but actions on the client, such as moving messages, marking read, and so on, do not feed back to the server, such as 3 of messages in the mailbox and moved to other folders by the client, and the messages on the mailbox server are not moved at the same time.
While IMAP provides two-way communication between the webmail and the email client, the client's actions are fed back to the server, the messages are manipulated, and the messages on the server do the corresponding actions.
At the same time, IMAP, like POP3, provides a convenient e-mail download service that allows users to read offline. The summary browsing feature provided by IMAP allows you to decide whether or not to download after you have read all the message arrival time, subject, sender, size, and so on. In addition, IMAP is better able to support access to new messages from multiple different devices at any time.