How to Install Postal Mail Server on Rocky Linux 8

Postal is a complete and fully featured mail server for use by websites & web servers. Think Sendgrid, Mailgun, or Postmark but open source and ready for you to run on your servers. Postal is developed by Krystal to serve its mail processing requirements and we have since decided that it should be released as an open-source project for the community. In this article, we are going to learn how to install Postal Mail Server on Rocky Linux 8. So, let’s get started.

Checkout the Postal Mail Server Project Here.

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Pre-requisites :

  • A system with Rocky Linux 8 installed and running.

  • root access to the system.

  • Docker installed and running, for this, you can refer to one of our guides on installing the Docker on Rocky Linux 8.

  • LAMP Stack installed and running, for this, you can refer to one of our guides on installing the LAMP Stack (Apache, MariaDB, and PHP).

Once you're all set, we'll proceed with Postal Mail Server installation and configuration.

Install Git, Curl & JSON data

There are a few system utilities that you need to have installed before you'll be able to run some of the Postal commands.

yum install git curl jq

Download Postal Git Repository

Let's download Postal Git Repository using the below commands

git clone /opt/postal/install

ln -s /opt/postal/install/bin/postal /usr/bin/postal

Setup Database Connection using Docker

Postal requires a database engine to store all email and other essential configuration data. Let's setup using Docker.

Ensure that there's no other service running on port 3306.

docker run -d \
 --name postal-mariadb \
 -p \
 --restart always \
 -e MARIADB_DATABASE=crowncloud \
 -e MARIADB_ROOT_PASSWORD=crowncloud_password \

The above commands will setup the database with user crowncloud. We would suggest using a strong and long password.

Install RabbitMQ using Docker

RabbitMQ is responsible for dispatching messages between different processes. Let's setup using Docker.

docker run -d \
 --name postal-rabbitmq \
 -p \
 --restart always \
 -e RABBITMQ_DEFAULT_USER=crowncloud \
 -e RABBITMQ_DEFAULT_PASS=crowncloud_password \

Install Postal Mail Server

Run the command below and replace with the actual hostname you want to access your Postal web interface at. Make sure you have set up this domain with your DNS provider before continuing.

postal bootstrap

Configure and add all the appropriate values for your installation in postal.yaml

nano /opt/postal/config/postal.yml

Change values of the section DNS


Replace with your actual domain name or IP Address. After that, save and exit.

Install Docker Compose using below commands

curl -L "$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

chmod +x /usr/local/bin/docker-compose

ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

Initializing the database using the below command

postal initialize

Create a user account for Postal using the below command

postal make-user

Let's start Postal Mail Server using the below command

postal start

Enable Firewall:

firewall-cmd --zone=public --permanent --add-port 5000/tcp

firewall-cmd --permanent --add-service=http

firewall-cmd --permanent --add-service=https

firewall-cmd --reload

Install Caddy Server using Docker

To handle SSL termination and all web traffic, you'll need to configure a web proxy. You can use anything that takes your fancy here - Nginx, Apache, HAProxy, anything - but in this example, we're going to use Caddy.

Let's install Caddy Server using Docker

docker run -d \
 --name postal-caddy \
 --restart always \
 --network host \
 -v /opt/postal/config/Caddyfile:/etc/caddy/Caddyfile \
 -v /opt/postal/caddy-data:/data \

Accessing and Managing Postal Mail Server

Now open the domain name from your browser, this will redirect you to configuring the final parts of the Postal Mail Server installation.

Replace the with the actual IP or domain configured on the server.

Now you have Postal Mail Server on your server. Follow the below images for Postal layout:

Now you have successfully installed Postal Mail Server on Rocky Linux 8.