SMTP  What is it and how does it work to send emails? ▷ 2020

Opening or sending an email is a simple task for most of us. However, you should know that for this to happen there is a server-client structure, where there is a user who is the one who sends the message and a server who is the one who processes and receives it.

For this to happen, the data that make up the email must be transferred, for which the SMTP protocol is used, which stands for “Simple Mail Transfer Protocol”, where certain rules are executed so that it can be sent. It goes without saying that without this protocol this could not happen.

The technique that exists today has a high quality in terms of sending and personalizing emails, since several of us use it frequently.

What is the SMTP Protocol and what is it for in computer networks?

SMTP is an email transmission system that, like TCP / IP, is integrated into Internet protocols. It is used with the intention that users can receive and send emails.

Usually used with POP3, or with the Internet message entry system called “IMAP”, which is used to protect the messages found inside the server’s mailbox, and then be able to download them constantly on the destination user’s server.

The referred protocol is the norms that are used with the intention of authorize the transmission of information within a computer network, being that SMTP itself is an Internet system.

There are cases where the SMTP It is only used for sending emails, as there are some technical limitations to be able to accept them. This makes it necessary for the reception to use other types of Internet systems, such as the Internet Message Access Protocol (IMAP) or Post Office Protocol (POP).

The above means that when an email is sent the IP address of a spammer is shared, which means that a circumstance occurs where the prestige of delivery is damaged, which predominates in the proper delivery of clean emails.

The moment the user sends an email using the SMTP protocol, what happens is that the email user, such as: Mozilla Thunderbird or Outlook Express sends a message through a server through SMTP. This server transports the message to the “Mail Transfer Agent (MTA)”, through the “Domain Name System (DNS)” in order to get the “MX record”.

As soon as the message is accepted, it passes to a “Mail Delivery Agent (MDA)”, which may need to run SMTP again with the intention of being able to deliver it to the email server. It is then, that through “IMAP” the receiving person obtains or retrieves his message in his email account.

What is the SMTP server of the most important email services and how to use them for free?

Next, we will explain how the SMTP protocol works with the most common email services used by users:

Google gmail


It is a totally free server that is used for those companies or people who do not handle a large volume of emails. It is an excellent option when you need to use Gmail and you need to send chain emails.

Gmail itself has a very large space, so it is to be trusted when it comes to wanting to use its services online. But has certain limits, since it only allows one hundred emails to be sent in an estimated time of 24 hours when they want to be reproduced using the SMTP protocol. This would result in 3,000 free emails for a period of 1 month.

The amount indicated above may be sufficient when your business is small, since If you want to increase the fee, you will have to cancel the amount charged for the payment service. The information you submit is available anywhere you need it.

Microsoft Outlook / Hotmail


This is one of the e-mail services most used by Windows users, since in itself comes pre-installed on systems and helps people to communicate via messages with other people through the SMTP system, you can also access emails through the POP3 or IMAP protocols.

We must say that it is very complete, since you can enjoy anti-spam filters, shared mailbox, calendar organizer, task organization, contact filter, calendar, search for messages and be able to customize it your way. It is also programmed and used to work with the mail protocols of your choice.



The SMTP servers at Yahoo are used for outgoing emails, which means that for your incoming emails other types of protocols such as POP or IMAP are also used. In general, these protocols are found in the configuration tab where you add the Yahoo account.

These types of Yahoo protocol can be found on Google anytime. They are also used with much more protection through an additional security layer that is located in your Yahoo! account.

That is why when another user wants to access your email, it is blocked by this server in case your security is not standard. It is important that you know that it is not good that you activate the option “Less secure applications”, as this can be a danger to your account and to your personal information.

It is recommended that before setting up your email check very well what each option is for, and thus avoid any type of inconvenience with your account.

What are the main characteristics of the SMTP network protocol?

Through the years, emails have been a means of communication for Internet users, one of the most used protocols being SMTP, which means “Protocol for Simple Mail Transfer”.

Among its essential characteristics we can indicate the following:

  • It has text commands that are very easy to use.
  • It is a network protocol used for electronic messages.
  • Helps users stay in touch through a server, as messages are sent and received.
  • It has lines of text where the instructions for this system are specified.
  • They provide the option of being able to exchange e-mail messages through “TCP / IP hosts”.
  • It is made up of 3 protocols that are standard and that apply to emails, among which are: MAIL, DATA and RCPT
  • It can be configured together with other protocols such as: POP3 or IMAP.
  • Sometimes SMTP is only used for outgoing emails, while POP3 or IMAP are used for incoming emails.
  • Through it there is the option of being able to synchronize a Smarthost server.

SMTP vs POP3, which is better and how are they different?

Both protocols are used to manage emails on the Internet, but it should be made clear that each one fulfills a different function in the dynamics of sending and receiving emails.

Among the most prominent differences we have the following:

  • SMTP is used to send messages; while POP3 is running to receive them.
  • With SMTP is the forwarding server; and with POP3 is the receiving server.
  • SMTP sends email from the sender’s computer to the recipient’s mailbox; while with POP3 it is possible to recover, as well as organize the emails that are inside the recipient’s mailbox to the destination computer.

SMTP vs IMAP, which one is better and how is each one different?

In general, the emails are stored within the server of the email that has been entered and that have not been opened by the user.

However, when the user sends a message, it goes up to the server of the outgoing emails using the SMTP protocol and goes immediately to the recipient’s inbox.

Unlike the IMAP server, where the message is found on the receiving device without being downloaded from the server, that is, when an email has been opened on a device, when entering from another it leaves as read, and at the time the user makes the request, it is necessary to permanently connect to the Internet so that he can enter the email and view the message.

Because the messages do not need to be downloaded, it is much easier to read them. Also here it is achieved sort the folders, for any user to see. It should be noted that when a user makes some modification on the server, other users can see it. It is important that the period with which the user accesses new messages is programmed, something that can also be done manually.

If you have any questions, leave them in the comments, we will answer you as soon as possible, and it will surely be of great help to more members of the community. Thank you! 😉

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