Setting up a basic Postfix SMTP Server Using Docker

Note: These articles are based on LinuxBabe site but are rewritten to use docker.

Why run your own email server? Perhaps you have a website, which needs to send emails to users, or maybe you want to store your emails on your own server to protect your privacy. However, building your own email server can be hard because there are so many software components you need to install and configure properly. To make this journey easy for you, I’m creating a tutorial series on how to build your own email server on Docker.

I’m confident to say that this is the best and most comprehensive tutorial series about building an email server from scratch on the Internet. Not only will you have a working email server, but also you will have a much better understanding of how email works. This tutorial series is divided into 12 parts.

1. Setting up a basic Postfix SMTP server using docker
2. Set up Dovecot IMAP server and TLS encryption
3. Create Virtual Mailboxes with PostfixAdmin
4. Creating SPF and DKIM records to get through spam filters
5. Setting Up DMARC to protect your domain reputation
6. 7 Effective Tips to Stop Your Email From Being Marked as Spam
7. How to Host Multiple Mail Domains in PostfixAdmin
8. Blocking Email Spam with Postfix
9. Blocking Email Spam with SpamAssassin
10. Setting Up Amavis and ClamAV on Ubuntu Mail Server
11. How to Secure Email Server Against Hacking with Self-hosted VPN Server
12. Enable and Configure Postscreen in Postfix to Block Spambots

I know this seems to be a very daunting task. However, based on what you want to achieve, you might not need to follow all of them. These articles are easy to follow, and it helps you to have a working email server.

Hint: If you don’t want to build an email server from scratch, which is a long and tedious process, you can use iRedMail to quickly and easily set up a full-featured mail server.

This article is part 1 of this tutorial series. In this article, I will show you how to set up a very basic Postfix SMTP server, also known as an MTA (message transport agent) with docker. Once you finish this article, you should be able to send and receive emails with your own email domain on your own email server. This tutorial is tested on Linux and Docker version 20.10.

About Postfix

Postfix is a state-of-the-art message transport agent (MTA), aka SMTP server, which serves two purposes.

• It’s responsible for transporting email messages from a mail client/mail user agent (MUA) to a remote SMTP server.
• It’s also used to accept emails from other SMTP servers.

Postfix was built by Wietse Venema who is a Unix and security expert. It’s easy to use, designed with security and modularity in mind, with each module running at the lowest possible privilege level required to get the job done. Postfix integrates tightly with Unix/Linux and does not provide functionalities that Unix/Linux already provides. It’s reliable in both simple and stressful conditions.

Postfix was originally designed as a replacement for Sendmail – the traditional SMTP server on Unix. In comparison, Postfix is more secure and easier to configure. It is compatible with Sendmail, so if you uninstall Sendmail and replace it with Postfix, your existing scripts and programs will continue to work seamlessly.

In this tutorial, you will learn how to configure Postfix for a single domain.