E-mail is certainly very familiar to everyone, everyone who has a Facebook account must have e-mail. E-mail is a method for sending e-mail in digital form, usually using internet media. Now, there is an email tester that can be used by companies to find out whether the email they use is still active or not. This is useful for the development of their business because most of the communication between employees and the owner or the client uses email clearout.
If we send an e-mail from one e-mail address to another e-mail address, MTA (Mail Transfer Agent) software is used using a protocol called SMTP (Simple Mail Transfer Protocol). the SMTP protocol becomes the basic rules agreed upon for sending an email. so the email server software definitely supports this protocol.
SMTP is a protocol used to communicate between email servers, not email servers with clients. so for example between yahoo email with Gmail and to other email servers. To communicate between server and client, other protocols are used, namely IMAP, POP3, IMAPS, POP3S.
IMAP (Internet Message Access Protocol) functions as a protocol that allows email to be accessed by clients, as well as POP3 (Post Office Protocol version 3), it’s just different ways of accessing it.
SMTP is a standard protocol for sending an email on a text-based internet. This protocol mentions the recipient then verifies if true then the email will be sent immediately. This protocol uses port 25. Because this protocol is only based on ASCII text, it will not be perfect for sending messages such as images, sounds, movies, and programs. therefore the MIME standard is used. SMTP can only retrieve emails from the client but can serve email retrieval by the client, or more familiar SMTP can only do push, can not pull.
There are many SMTP software variants, the most famous of which is POSTFIX, Ms. Exchange Server, Qmail. the product is the most widely used product.
If we were discussing SMTP which can only do ‘push’, we will now discuss the protocol that functions to pull, the first being POP3. POP3 is a protocol that functions so that email can be retrieved by the client. there are two modes used by POP3 namely inline and offline modes. in offline mode, POP3 retrieves then deletes the email stored from the server and make it as ‘store and forward’. While POP3 in inline mode, POP3 will retrieve the mail server without deleting the mail that has been retrieved.
IMAP has the same function as POP3 but there are several advantages including being able to create folders on the server, retrieve e-mails, search e-mails and delete certain e-mails.