Configuring UFW Firewall for Your Server

Introduction

In this guide, we’ll walk through the essential steps to configure the UFW firewall on your server. Proper firewall configuration is crucial for securing your server against unauthorized access and ensuring that only necessary services are accessible.

Step 1: Install UFW

The Uncomplicated Firewall (UFW) is a simple and user-friendly tool for managing firewall rules on your server. Install UFW with the following command:

sudo apt install ufw

Step 2: Configure UFW Rules

Next, we’ll configure UFW to enhance your server’s security. We’ll set the default policies to deny all incoming traffic and allow all outgoing traffic. Then, we’ll open specific ports needed for SSH and web traffic.

1. Deny all incoming traffic:

sudo ufw default deny incoming

2. Allow all outgoing traffic:

sudo ufw default allow outgoing

3. Allow SSH traffic:
   Allowing SSH ensures you can still connect to your server remotely for administrative purposes:

sudo ufw allow ssh

4. Enable UFW:
   Enable UFW to activate your rules:

sudo ufw enable

5. Allow web traffic (HTTP and HTTPS):
   If your server will be hosting a website or web application, you need to allow HTTP and HTTPS traffic:

sudo ufw allow http
sudo ufw allow https

Example: Allowing and Disallowing Specific Ports

Sometimes, you may need to allow specific ports for particular services temporarily or permanently.

Allowing a Specific Port:
For example, if you need to allow port 8080 for a web application, you can do so with:

sudo ufw allow 8080/tcp

Disallowing a Specific Port:
If you no longer need to keep port 8080 open, you can disallow it with:

sudo ufw delete allow 8080/tcp

Step 3: Verify UFW Status

After configuring the rules, it’s important to verify that UFW is active and the rules are correctly applied:

sudo ufw status verbose

This command displays the current status of UFW and the rules that are in place.

Conclusion

By following these steps, you have configured the UFW firewall to secure your server against unauthorized access while allowing necessary traffic. This basic configuration ensures that only essential services are accessible, providing a solid foundation for further server setup and security measures. Remember, you can always adjust the firewall rules as needed for your specific use case.