Introduction

UFW (Uncomplicated Firewall) is a user-friendly interface for managing iptables firewall rules on Linux systems. It's a great tool for securing your VPS by controlling incoming and outgoing traffic. This guide will cover the basics of setting up and using UFW on your Linux server.

Step-by-Step Guide

Step 1: Install UFW

1. Most distributions come with UFW pre-installed. If it’s not installed on your system, you can install it with:

   sudo apt install ufw

Step 2: Allow SSH Connections

Before enabling the firewall, you need to ensure that SSH connections are allowed, so you don't get locked out:

sudo ufw allow ssh

If you are using a different SSH port, specify it like this:

sudo ufw allow 2222/tcp

Step 3: Enable UFW

To turn on the firewall, use the following command:

sudo ufw enable

Step 4: Allow or Deny Specific Ports

• Allow a specific service by name (e.g., HTTP):

  sudo ufw allow http

• Allow a specific port:

  sudo ufw allow 80

• Deny a specific port:

  sudo ufw deny 23

Step 5: Check UFW Status and Rules

To view the status of UFW and the active rules, use:

sudo ufw status verbose

Step 6: Disable UFW

If you need to temporarily disable the firewall, run:

sudo ufw disable

Conclusion

By setting up a firewall with UFW, you've added a critical layer of security to your Linux VPS. Regularly review your firewall rules to ensure no unnecessary ports are open, thereby maintaining a robust security posture.

Disclaimer

Be cautious when configuring your firewall rules to prevent accidental service disruptions, especially SSH connectivity to your server.