How To Set Up a Firewall Using firewalld on Rocky Linux 9

Introduction

firewalld is a firewall management tool available on many Linux distributions, including Rocky Linux. It provides a dynamically managed firewall with support for network zones to define the level of trust for network connections or interfaces.

Setting up a firewall is crucial for ensuring the security and integrity of your system. In this guide, we’ll walk you through the process of setting up a firewall using firewalld on Rocky Linux 9 and opening ports 5672 and 15672, which are commonly used by RabbitMQ.

Prerequisites

• A system running Rocky Linux 9
• Sudo privileges

Step 1: Installing firewalld

If firewalld is not already installed on your system, you can install it using the following command:

sudo dnf install firewalld

Step 2: Starting and Enabling firewalld

Once installed, start the firewalld service and enable it to start on boot:

sudo systemctl start firewalld
sudo systemctl enable firewalld

Step 3: Checking the Status of firewalld

To ensure firewalld is running, use the following command:

sudo systemctl status firewalld

Step 4: Opening Ports for RabbitMQ

RabbitMQ typically uses port 5672 for client connections and 15672 for the management plugin. To open these ports, use the following commands:

sudo firewall-cmd --zone=public --add-port=5672/tcp --permanent
sudo firewall-cmd --zone=public --add-port=15672/tcp --permanent

Step 5: Reloading firewalld

After making changes, reload firewalld to apply them:

sudo firewall-cmd --reload

Step 6: Verifying the Open Ports

To verify that the ports are open, use:

sudo firewall-cmd --list-all

This command will show all settings, including open ports in the current zone.

Conclusion

Your Rocky Linux 9 system now has a running firewalld firewall with ports 5672 and 15672 open for RabbitMQ. This setup enhances your system’s security while allowing necessary traffic for RabbitMQ.

Remember, firewall management is a critical aspect of system administration. Regularly check and update your firewall settings to ensure optimal security.

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