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Free SMTP Server: What it is and how to configure it?

The SMTP server is a computer that receives emails sent by a person and delivers them to their respective recipients. It works just like the Post Office service, in which the postman collects and sends mail in a standardized and secure manner.

The digital universe is very similar to the real world. Just as a letter needs to follow some standardization rules and follow a specific path from its sender to the recipient, emails must follow a specific protocol from the server from the click on the “send” button to the destination inbox.

SMTP – Simple Mail Transfer Protocol – is the simple email transfer protocol, which defines the standardization of the information that identifies each email and the path it must take to be delivered in a complete, confidential and secure manner. Among the different steps, passing through an SMTP server is one of the most relevant.

Want to better understand how it all works? In this context, you will see the topics:

  • Understand what an SMTP server is and what it is for
  • Find out how an SMTP server works
  • Learn how to configure the free SMTP server on the 4 most used free platforms

Understand what an SMTP server is and what it is for?

Just as creating a website is not something very familiar to anyone who is not directly connected to the technology area, the backstage of sending an email generates many doubts. So let’s start by clarifying the main ones. Check out!

What is an SMTP server?

The SMTP server is a computer that intermediates between sending and receiving email messages. He is responsible for receiving the information from the sender and sending it to the internet so that a POP / IMAP server receives it and directs it to the recipient’s box.

Why can’t you send an email without an SMTP server?

Going back to the correspondence system analogy in the real world, imagine that you need to tell a relative who lives in another state about the birth of a new family member.

You will write a letter, put it in an envelope with all the identification information and deliver it to a post office or to the postman who passes on your street.

Now, imagine if there was no courier service and you needed to send that same letter. You would have to look for alternative routes, like people on the way to the place or something. All of this without being sure that the message would be delivered to the right address, without being tampered with or altered.

The SMTP server fulfils this role of intermediation. It checks shipping requirements to ensure that the email is delivered in its entirety, to the right person and in the shortest possible time.

What is the difference between paid and free servers?

When choosing an SMTP server, many people wonder if the free servers are reliable, since there are paid versions on the market, as is also the case with CMS tools.

The answer is: yes, they are quite reliable and that is not the difference for others. The most relevant point is related to the shipping capacity and quality, as we will explain below.

Shipping capacity

On free servers, such as Gmail, Yahoo and Outlook, the daily limit for sending messages are lower, at around 100 messages. For those who do not use this channel to send email marketing, it is a very reasonable amount.

In paid platforms, the limit varies according to the plan and the company, but, in any case, they are larger quantities, specific for those who make more massive use. If your customer base is large and you want to send campaigns, paid services are more suitable.

Shipping quality

One of the characteristics evaluated by the POP / IMAP servers, responsible for the final delivery of emails, is the reliability of the origin. Mass messages sent through free servers are not well regarded at this point since they share the IP address, similar to the practices used by spammers and malware.

This means that, when choosing the box to which the email will be directed, the chances of it going to spam or even directly to the trash are much greater. As a consequence, the recipient tends to be more suspicious of your email, not open it or even ask that your contact be removed from the mailing list, damaging your sales strategy.

Find out how an SMTP server works

The operation of an SMTP server is very simple to understand. When a person writes an email and clicks send, all information about it is sent to the SMTP server.

At that moment, the server will adapt the received content to the standards of the email transfer protocol and forward it to the internet, where it will be transmitted: similar to what the postmen do when collecting the mail to be sent.

They organize according to destinations and identify packages according to the company’s internal rules. Then, the bags are transported to the next checkpoint, which will be the agency responsible for making the final delivery.

In the case of emails, this role is performed by a POP / IMAP server, which takes messages received on the internet and takes them to the recipients’ boxes. Just like postmen do every day on the streets, but digitally and in a few seconds.

Learn how to configure the SMTP server on the 4 most used free platforms

Currently, most people access their email boxes via webmail or smartphone application. For these options, it is not necessary to configure the SMTP server, as access is granted through login and password.

For those who prefer to access messages locally, or even maintain a backup outside the cloud, access is done differently.

You must use email client software, such as Microsoft Outlook or Mozilla Thunderbird, which is installed on the machine and works both online and offline.

General information for the configuration

If this is the first time that the email client is accessed, the configuration screen will be loaded automatically. Otherwise, just enter the software settings and look for the option for the SMTP server. The arrangement of the requested information may vary, but will have:

  1. user name: your name;
  2. user email: the email address that will be accessed;
  3. SMTP server: varies as we will explain later;
  4. user: the same one used to perform the login;
  5. access password: the same password used to access the email;
  6. exit port: varies as we will explain later;
  7. gateway: 993 if it is a POP server or 995 if it is IMAP.

Specific information about the main free servers

As you can see, some information requested in the configuration is variable, according to the platform chosen. We brought the data of the most used currently free of charge so that you can do it on your computer.


The specific data of the Gmail SMTP server is:

SMTP server:;

outgoing port: 465 if using SSL or 587 if using TLS.


The specifics of the Hotmail SMTP server are:

SMTP server:;

exit port: 25 or 465.


The specific data of Yahoo’s SMTP server is:

SMTP server:;

exit port: 465.


The specific data of the SMTP server is:

SMTP server:;

exit port: 587.

After all this information, it became easier to understand the operation of an SMTP server and its importance. When choosing the platform, remember to analyze the volume of your shipping demand. If low, free servers are sufficient; otherwise, it is best to hire a plan that allows you to take larger flights in your business.