Introduction

Iptables is a powerful firewall utility for Linux systems that allows you to configure rules to control incoming and outgoing network traffic. In this guide, we'll walk through the steps to set up an iptables firewall to protect traffic between your servers.

Prerequisites

Before proceeding, ensure you have:

1. Multiple Linux servers connected to a network
2. Root access or sudo privileges on each server

Steps to Set Up an Iptables Firewall

1. Install iptables: If not already installed, install iptables on each server:

sudo apt update
sudo apt install iptables

1. Define Firewall Rules: Define iptables rules to control traffic between your servers. For example:

sudo iptables -A INPUT -s <source_IP_address> -j ACCEPT
sudo iptables -A OUTPUT -d <destination_IP_address> -j ACCEPT
sudo iptables -P INPUT DROP
sudo iptables -P OUTPUT DROP

1. Save Firewall Rules: Save iptables rules to persist across reboots:

sudo iptables-save > /etc/iptables/rules.v4

1. Enable Firewall: Enable the iptables firewall:

sudo systemctl enable iptables
sudo systemctl start iptables

Conclusion

Congratulations! You have successfully set up an iptables firewall to protect traffic between your servers. Your servers are now more secure and less vulnerable to unauthorized access or malicious traffic.