SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used to send and receive e-mail between servers.Decryption is performed by using the TCP/IP protocol."p style="box-sizing: border-box; line-height: 23px; margin-top: 0px; margin-bottom: 1rem;">SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used to send and receive e-mail between servers. However, since it is limited by the ability to queue messages on the receiving side, it is used in conjunction with POP3 (Post Office Protocol) or IMAP (Internet Message Access Protocol), one of the other two protocols that allow the user to save messages. In other words, users usually use a program that uses SMTP to send e-mail and POP3 or IMAP to receive e-mail.

How Does SMTP Work?

The SMTP service works by using a three-stage process model in the order of client, sending server, receiving server. In other words, first, the SMTP protocol is used to send a message from Outlook or Webmail and a similar e-mail client to the sending e-mail server. In the second stage, the sending e-mail server uses SMTP as a migration service to send e-mail to the receiving e-mail server. Finally, the receiving server uses an email client (Outlook, Webmail, etc.) to download the incoming mail via IMAP or POP3.

SMPT can perform operations such as forwarding mail, forwarding to another server name (relay), or forwarding mail. In order to receive, read or index mail, it is necessary to use the IMAP protocol. So in summary, if we are using a mail client, we need to configure the SMTP settings for sending and IMAP or POP settings for receiving.

History of SMTP

Although various methods have been used in electronic communication since the 1960s, the SMTP protocol was first standardized by POSTEL in 1982, and published with the code rfc788. Immediately after that, Sendmail published with the code rfc788. Over time, open source linux operating systems have become very popular in server services, so SendMail (MTA) has become the most popular mail transfer agent. Hundreds of different Mail Server service software have been published today. The most popular ones are Exim, Postfix, Qmail, Mail Enable, Microsoft Exchange, Icewarp, hMail, etc. As examples, we can show the software.

How Many SMTP Ports is it?

SMTP protocol, 25, 3 different ports and 2 different security layers (587, 465 and SSL or TLS) is being used. Port number 587, usually called SMTP Submission between the client and the sending server, and the TLS security layer is the most widely used. Decryption is done by the following methods: SMTP Submission.span>. Between the servers that send and receive mail, port Dec. 25 is used as standard. If mail transmission between two servers is to be done with secure Decryption, SSL or TLS uses port 465. You can ask a question why 587 is used Decoupled between the client and the sending server. Many years ago, service providers in Turkey decided to close port 25 in IP blocks used for ADSL in the fight against spam, so port 587 is used Decoupled between the client and the server. After this application, Turkey suddenly lost its ranking among the countries sending spam mail quickly and solved this problem.