The Simple Mail Transfer Protocol (SMTP) server is a communication protocol or the technology behind email communication. In other words, SMTP is the protocol that allows you to send and receive emails. Every SMTP server has a unique address and needs to be set up in the mail client that you are using. If you are using SMTP host Gmail for example, then the SMTP address is If you want to find the address of the SMTP server you are currently using, you can easily find it in your email client settings.

Why You Need An SMTP Server?

Without an SMTP server, you cannot send your email to its destination. When you click the “send” button from your email client, your email messages get automatically converted into a string of codes and are transferred to your SMTP server. There, the codes are processed accordingly, and the message is relayed to the correct email address. If there is no outbound SMTP server, then the email message cannot be sent to the recipient and could even get lost in the conversion process.

Along with relaying SMTP email messages, the server also checks whether an active or working email account is sending the outgoing message. In case the email cannot be delivered, it ensures that the email goes back to the sender. This action is to let the sender realize that he has the wrong email address or the receiving server blocks emails from the sender’s ID.


How SMTP Server Works?

When you send an email, this is what happens in the background in the SMTP server (let’s assume that Outlook Express is used here to send the email):

  • The email client (Outlook Express) connects to the SMTP server through the specified port (say 25).
  • The email client communicates with the SMTP server with all the details of the email message, including the sender email ID, receiver email address, and body of the email.
  • Now the SMTP server springs into action and breaks the recipient email address into two parts, name and domain name. For example, if the recipient name is, the email address is split into john and
  • If the sender email address also comes from, the process is quick and straightforward for the SMTP server. It uses a delivery agent program to deliver the email to that address using the POP3 server for Gmail. But if you are using a hosted SMTP server, then the process takes some time.
  • Every domain name, like the free SMTP hosting provider, Gmail, has a unique IP address, and the SMTP server gets the IP address of the recipient. The server checks whether the sender’s email address is an active address to prevent spam emails and then hands over the message to the recipient SMTP server.
  • The recipient SMTP server then takes care of delivering the email address to the recipient’s inbox.
  • In case the recipient email address is incorrect, or if the recipient SMTP relay service rejects the email message from the sender, it returns the email to the sender with appropriate information.


How To Configure An SMTP Server In 4 Simple Steps

Setting up an SMTP server is pretty simple. Follow the steps as detailed below:

Step 1: Open the email client and go to Tools à Account Settings.

Step 2: Choose “Outgoing Server (SMTP).”

Step 3: Click the “Add” button to add a new SMTP server.

Step 4: In the next window, provide all details including your description, server name, port address, connection security, authentication method, and username.

Description: In the description field, give a name to identify your email server. If you are setting up your Gmail account in Outlook, then provide Gmail. If you are setting your company email address, then give it as Company Mail, and so on.

Server Name: This is where you will provide the SMTP server name of your email account. If you are setting your Gmail account, give as the server name. You can also buy SMTP server from email hosting providers and provide the address of that here.

Port: Generally, port 25 is used for sending emails. But port 587 can also be used to send emails.

Connection Security: By default, SMTP servers don’t encrypt email messages. But if you need to use encryption, then you can use the SSL/TLS extension, too.

Authentication Method: If you want to use a password, then you can choose “Password, transmitted insecurely.”

Username: Provide the username of the email address.


How To Check If Your SMTP Server Is Working?

At times, even though you provide the right email address and SMTP server, the mails won’t go through. So, to test whether your SMTP server is working or not, you can use the following method


  • Open command prompt, type telnet along with your SMTP address and port address like: telnet 25
  • If the SMTP is working, then a message with the status code 220 is returned.
  • If there is no response, then it means some antivirus or firewall is blocking your SMTP server from relaying your message.

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