How to Configure Ufw Firewall on Ubuntu 24.04

ByAkensai

Learning how to configure UFW firewall on Ubuntu 24.04 is one of the first things you should do after setting up a new server. UFW (Uncomplicated Firewall) is a user-friendly interface for managing iptables rules. It makes firewall management straightforward without requiring deep networking knowledge. Whether you’re running a web server, a WordPress site, or a development environment, a properly configured firewall is your first line of defense. In this tutorial, you’ll learn how to install UFW, set up default policies, allow specific services, and verify your rules are working correctly. By the end, your Ubuntu server will be protected against unauthorized access while still serving legitimate traffic.

Prerequisites to Configure UFW Firewall on Ubuntu 24.04

Before you start, make sure you have the following in place:

Required access and software:

  • A server or VPS running Ubuntu 24.04 LTS
  • A non-root user with sudo privileges
  • SSH access to your server
  • Basic familiarity with the Linux command line

Estimated time: 15–20 minutes

One important warning before you begin. If you’re connecting via SSH, always allow SSH traffic before enabling UFW. Failing to do this will lock you out of your server. Port 22 is the default SSH port. If you changed it, use your custom port number instead.

UFW comes pre-installed on Ubuntu 24.04. However, it may not be active yet. You’ll confirm this in the steps below. According to the official Ubuntu UFW documentation, UFW is designed to make iptables configuration easier for everyday users and administrators alike.

Step-by-Step Guide to Configure UFW Firewall on Ubuntu 24.04

This event shares similarities with: How to Set Up Nginx Reverse Proxy with Let’s Encrypt Ssl on Ubuntu

Follow these steps carefully. Each step builds on the previous one.

Step 1: Update your package list

Always start with a system update. This ensures your packages are current.

sudo apt update && sudo apt upgrade -y

Step 2: Install UFW (if not already installed)

Check if UFW is installed. If it isn’t, install it now.

sudo apt install ufw -y

Step 3: Check the current UFW status

Before making changes, check whether UFW is already active.

sudo ufw status verbose

You’ll likely see Status: inactive. That’s expected on a fresh install.

Step 4: Set default policies

Default policies control what happens to traffic that doesn’t match any rule. Set incoming traffic to denied and outgoing to allowed.

sudo ufw default deny incoming
sudo ufw default allow outgoing

This blocks all incoming connections by default. You’ll then open only the ports you need.

Step 5: Allow SSH connections

This step is critical. Allow SSH before enabling the firewall.

sudo ufw allow ssh

If you use a custom SSH port, replace ssh with your port number:

sudo ufw allow 2222/tcp

Step 6: Allow common service ports

Now open ports for the services your server runs. Here are the most common examples:

Allow HTTP traffic (port 80):

sudo ufw allow http

Allow HTTPS traffic (port 443):

sudo ufw allow https

Allow both HTTP and HTTPS using an app profile:

sudo ufw allow 'Nginx Full'

If you’re running Apache instead of Nginx:

sudo ufw allow 'Apache Full'

You can list all available app profiles with:

sudo ufw app list

Step 7: Enable UFW

Once your rules are in place, enable the firewall.

sudo ufw enable

You’ll see a confirmation prompt. Type y and press Enter. UFW will activate immediately.

Step 8: Verify your rules

Check that everything looks correct.

sudo ufw status numbered

This shows all active rules with numbers. The numbered format is useful when you need to delete a specific rule later.

Step 9: Delete a rule (optional)

If you added a rule by mistake, delete it using its number.

sudo ufw delete 3

Replace 3 with the actual rule number from your status output.

Step 10: Allow connections from a specific IP address

You can restrict access to a specific IP. This is useful for database ports or admin panels.

sudo ufw allow from 203.0.113.10 to any port 3306

This allows only the IP 203.0.113.10 to access MySQL on port 3306.

For more advanced iptables configuration options, check the UFW man page on Ubuntu 24.04 for a full list of supported syntax and flags.

Troubleshooting Common UFW Firewall Issues

Even with careful setup, things can go wrong. Here are the most common problems and how to fix them.

Problem: Locked out of SSH after enabling UFW

This happens when you forget to allow SSH before enabling the firewall. If you have console access through your hosting provider, log in there and run:

sudo ufw allow ssh
sudo ufw reload

If you don’t have console access, you may need to rebuild your server. This is why Step 5 is so important.

Problem: UFW is active but traffic is still blocked

Check your rules carefully with sudo ufw status verbose. Make sure the port and protocol match your service. Some applications use UDP instead of TCP.

sudo ufw allow 53/udp

Problem: UFW rules aren’t persisting after reboot

UFW rules should persist automatically. If they don’t, check that the UFW service is enabled:

sudo systemctl enable ufw
sudo systemctl start ufw

Problem: Nginx or Apache not accessible after enabling UFW

You may have only allowed port 80 but not 443. Use the full profile to cover both:

sudo ufw allow 'Nginx Full'

Then reload UFW:

sudo ufw reload

Tip: Disable UFW temporarily for testing

If you need to test whether UFW is causing a connectivity issue, disable it temporarily:

sudo ufw disable

Remember to re-enable it after testing. Never leave your firewall disabled on a production server.

Tip: Reset all rules and start fresh

If your rules are a mess, reset everything and start over:

sudo ufw reset

This disables UFW and removes all rules. You’ll need to reconfigure from Step 4.

Conclusion

You now know how to configure UFW firewall on Ubuntu 24.04 from start to finish. You’ve set default policies, allowed essential services, enabled the firewall, and learned how to troubleshoot common issues. A properly configured firewall is a non-negotiable part of any secure server setup. It protects your services from unauthorized access and reduces your attack surface significantly.

Your next steps should include setting up Fail2Ban to block repeated failed login attempts. You should also review your open ports regularly and close anything you don’t actively use. Keep your system updated and audit your firewall rules every few months. Security isn’t a one-time task. It’s an ongoing process.

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