How To Set Up an SMTP Server on Ubuntu

Email servers are now a must-have for small, medium, and large enterprises. They enable easy and efficient traffic control. Besides, having your email servers ensure that you can independently define or set your rules to meet your objectives. These advantages ensure that you manage your servers more efficiently and in a cleaner manner.

SMTP is your ideal protocol for email server management. Commonly known as Simple Mail Transfer Protocol, SMTP stands out as a standard internet communication protocol designed and used for electronic mail transmission.

It routes emails by using third-party service providers to send emails through servers. This protocol comes in handy for companies or enterprises with large volumes of emails. Notably, SMTP has no downtimes, sends emails to your inbox rather than your spam folder, and has an analytics section on the dashboard. Thus, you do not need a lot of time and resources to manage your email servers.

This article demonstrates how you can set up an STMP server on Ubuntu 22.04. The same steps apply if your machine runs on Ubuntu 20.04.

Step 1: Update Your Server

The first step is to log in to your server and update it. You can log in using SSH, ensuring your server runs on the latest Ubuntu packages. Instead of SSH, you can also use CTRL+ALT+T to access your server. You can then execute the following command:

Step 2: Install Postfix

Once your server is up to date, install Postfix using the following command to install the email utilities:

A Postfix configuration window will pop up in the process of installation. The window will be shown below:

The configuration comes with Internet Site as the default mail configuration type. That is the recommended type of configuration for this particular purpose. Thus, you should press TAB, select OK, and then press ENTER.

Step 3: Configure Postfix

Now, configure Postfix to enable it to send and receive emails from the running server. In this case, the running server is the localhost. You can achieve this configuration process by setting up Postfix to listen exclusively on the loopback interface. This interface is a virtual network used by servers to communicate internally.

Make the relevant modifications by editing the primary Postfix configuration file (main.cf), which exists in etc/postfix. However, back up the file before you make any edits. You may need the original version.

You can then access the file using the following commands:

Find the following lines from the file:

Focus on inet_interfaces and set its value to loopback-only, as indicated below.

Step 4: Apply Changes and Start the Postfix Server

Ensure that you save the file once you make the necessary changes in the Postfix configuration file. You can then enable Postfix and start it using the following utilities:

Step 5: Configure Firewall

The firewall may restrict Postfix. You can allow all Postfix functions in the firewall using the following commands:

Step 6: Test the STMP Server

Use Telnet to confirm if the server is functioning properly. The following command should help:

A perfectly working Postfix should return the following results:

Proceed to install the mail-sending packages of Postfix. This is possible using the following command:

Run the following command once the installation is complete. The utility should help finish up the setup process.

When testing, please feed in your actual email address where necessary.


The tutorial provided a step-by-step guide on how to set up an STMP server with Postfix. As you probably know, a Postfix server allows the implementation of the SMTP protocol to help manage mail sending. It is fast, easy to configure, and incredibly secure hence popular among enterprises that handle bulk emails.

About the author

Kennedy Brian

Brian is a computer scientist with a bias for software development, programming, and technical content development. He has been in the profession since 2015. He reads novels, jogs, or plays table tennis whenever not on gadgets. He is an expert in Python, SQL, Java, and data and network security.