What Port You should Use When Generating An SMTP Connection?

Puneet Sharma


When we hire an email service, we are often presented with various information on how to configure email in our email client. One of the most common things is to try to configure the SMTP port correctly, in order to send mail successfully.

That is why today we will be covering everything related to the SMTP port since choosing and configuring an SMTP port can be somewhat complicated at first, due to the fact that there are several guidelines to take into account when establishing the connection.

We must also be sure that our email service supports and has said port enabled, as well as knowing if they have the encrypted connection enabled, to improve the security of your email communications.

Next, we are going to explain what port we should use when generating an SMTP connection in our mail client such as Outlook.

What is SMTP?

To be more understood on the subject, as a first step, we are going to explain what the SMTP port is and what functionality it fulfills in our daily lives.

SMTP is an acronym that comes from English and means Simple Mail Transfer Protocol or in Spanish known as Protocol for Simple Mail Transfer which is the basic standard used by most mail servers to allow emails to be sent through from the Internet.

In effect, this protocol is a set of rules that complies with and is present in the exchange of email messages between computers or mobile devices such as cell phones or tablets.

The SMTP uses a process known in Spanish as store and send where it does the function of sending our emails through the Internet.

This process is carried out directly with a program or software known as an email transfer agent or with the acronym in English MTA, which is in charge of sending the emails to the computers of our recipients.

The so-called MTAs are all those applications or programs that allow you to configure any email box to send and receive our messages, such as mail clients such as Microsoft Outlook, Thunderbird, Mailbird, Apple Mail, among many others that exist on the market.

In addition to having a process for sending emails, we also need to receive emails from the people who send them to us, which is why SMTP works with 2 protocol standards called POP3 or IMAP, which work in a similar way to SMTP but in reverse, that is to say, that it is also necessary that we connect to our mail servers but this time not to send but to download and receive the emails that have been sent to us and for this reason, it is that the SMTP is said to work in conjunction with POP3 or IMAP already that each complements the other.

To learn more about POP and know the difference with IMAP, you can see our article on the POP Server, where this topic is also discussed in depth.

What is the process of sending emails?

Now that we know that we need an email client or program to send and receive our emails, we would like to better explain in a few words how sending emails works.

Its process consists of some steps where the first starts from our mail client which must connect to our SMTP server using the appropriate configuration that our email service indicates ( continue reading to know what configuration you must use to connect to our mail servers ).

After that point and we are sure that our mail client is correctly connected to our server, when sending the mail our SMTP server connects with the recipient's server through a series of rules and if it is approved the message is received and stored waiting to be downloaded.

Finally, the recipient's mail client connects to the POP/IMAP server and checks if it has any mail to download and if so, downloads it and stores it in our inbox.

It could be said that in broad strokes and in a simple way, this is the operation and the steps that are carried out by the sender and receiver when sending an email.

What are the SMTP ports?

As we have talked about at the beginning of this post, there are several configurations and ports that we can use when generating a connection from our mail client or program to our SMTP server and that is why we are going to comment on the most common ports used in the present by means of a comparative table and then explaining a little each one of them.

Port 25

Port 25 is the default or standard port on all SMTP servers that exist today. It connects through the server without any type of encryption, this means that the message and the data travel in plain text, that is, without protection, for this reason, although this port is the default one, it is not the most recommended for use when generating a connection.

Although, as we mentioned before, it is the default port, it is not widely used today because a large amount of spam is sent by itself and for this reason, several email services have this port blocked, that is why It is always suggested to use other types of ports such as those that we will name below.

Port 25 is enabled for sending emails since even though a large part of the email servers have it blocked, there is another percentage that does not have it, and therefore on our site, we offer the possibility of being able to use it be necessary no matter how much we always recommend using any of the ports that we will name below.

Port 26

In the mail servers port 25 on 26 enabled as auxiliary, for any problem or in case there is some type of blockage from your Internet provider at the time of generating the connection, they can also try using port 26 which meets and has the same characteristics as the one mentioned above.

Port 2525

In other hosting services, they choose to enable port 2525 as an auxiliary to port 25, this fulfills the same function as port 26 that we have enabled in our company.

Port 587

In this case, port 587 is an auxiliary port for sending mail, which, although it is not the default port, is used by the vast majority of servers to send emails in a secure way. For example, if we want to configure a Gmail box either in a program, on our website, or in our mail client, it is certain that port 587 will work and we will be able to send without problems using TLS encryption.

Port 465

465 is the SMTP port that we should use in every connection since it works and connects in an encrypted way, which allows us to have greater security when sending our emails since they are fully encrypted, so if for any reason Some person wants to intercept or obtain our sent emails, it will be much more difficult to do so.

Something important to keep in mind is that in order for us to use this port that works through encryption, we will need the hostname that we have placed to connect to have an SSL Certificate installed, otherwise we will not be able to make the connection to our server.

Something very important to note is that although these ports are the most common and most used today, I do not want to say that they are the only ones that exist, since in a hosting service they may have other alternative enabled ports to open strictly for the sending emails, for this reason, whenever you have any questions or queries about which port to use when generating the connection, do not hesitate to consult the company that provides the service.

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A serial entrepreneur and passionate SaaS Marketer working in multi online business niches like hosting, eCommerce, saas, real estate.

Waneta, KY

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