How to Configure Ufw Firewall on Ubuntu 24.04 to Secure Your Server

ByAkensai

Learning how to configure UFW firewall on Ubuntu 24.04 to secure your server is one of the most important steps you can take after setting up a new VPS or dedicated machine. A misconfigured server with open ports is an easy target for attackers. UFW, which stands for Uncomplicated Firewall, gives you a simple command-line interface to manage iptables rules without needing deep networking knowledge. By the end of this tutorial, you’ll have a properly locked-down server that only allows the traffic you actually need. You’ll block unauthorized access, allow essential services like SSH and HTTP, and verify your rules are working correctly.

Prerequisites to Configure UFW Firewall on Ubuntu 24.04 to Secure Your Server

Before you begin, make sure you have the following in place.

What you need:
– A server running Ubuntu 24.04 LTS
– Root or sudo access to the server
– SSH access already working (don’t lock yourself out!)
– Basic comfort with the Linux command line

Estimated time: 15–20 minutes

Important warning: Always confirm SSH is allowed before enabling UFW. Blocking port 22 while connected via SSH will cut off your access immediately. If you’re working on a cloud provider like DigitalOcean or AWS, keep their console access open as a backup.

UFW comes pre-installed on Ubuntu 24.04. You won’t need to install anything extra. You can verify it’s available by running ufw --version in your terminal. If for any reason it’s missing, install it with sudo apt install ufw.

Step-by-Step Guide to Configure UFW Firewall on Ubuntu 24.04 to Secure Your Server

For more strange history, see: How to Create and Configure Custom Systemd Services on Linux

Follow these steps carefully and in order.

Step 1: Check the current UFW status

First, see whether UFW is already active on your system.

sudo ufw status verbose

You’ll likely see “Status: inactive” on a fresh install. That’s expected. Don’t enable it yet.

Step 2: Set default policies

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

sudo ufw default deny incoming
sudo ufw default allow outgoing

This blocks all inbound connections by default. You’ll open specific ports in the next steps.

Step 3: Allow SSH access

This is the most critical step. Allow SSH before enabling UFW.

sudo ufw allow ssh

This allows port 22. If you’ve changed your SSH port to something custom, use the port number instead:

sudo ufw allow 2222/tcp

Replace 2222 with your actual SSH port number.

Step 4: Allow HTTP and HTTPS traffic

If you’re running a web server, open ports 80 and 443.

sudo ufw allow http
sudo ufw allow https

Or use port numbers directly:

sudo ufw allow 80/tcp
sudo ufw allow 443/tcp

Both methods work. Using service names like “http” is easier to read in your rules list.

Step 5: Allow additional services if needed

For a MySQL database server, open port 3306. Only do this if remote database connections are required.

sudo ufw allow 3306/tcp

For FTP (though SFTP is preferred), allow port 21:

sudo ufw allow 21/tcp

You can also allow traffic from a specific IP address only. This is useful for restricting database access to your application server.

sudo ufw allow from 192.168.1.100 to any port 3306

Replace 192.168.1.100 with the actual IP address you want to whitelist.

Step 6: Enable UFW

Now that your rules are in place, enable the firewall.

sudo ufw enable

You’ll see a prompt warning that this may disrupt existing SSH connections. Type y and press Enter. UFW will activate immediately.

Step 7: Verify your rules

Check that everything looks correct.

sudo ufw status verbose

Your output should look similar to this:

Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW IN    Anywhere
80/tcp                     ALLOW IN    Anywhere
443/tcp                    ALLOW IN    Anywhere
22/tcp (v6)                ALLOW IN    Anywhere (v6)
80/tcp (v6)                ALLOW IN    Anywhere (v6)
443/tcp (v6)               ALLOW IN    Anywhere (v6)

Step 8: Delete a rule if needed

Made a mistake? Delete rules with the following command.

sudo ufw delete allow 3306/tcp

Or use the numbered rule list for easier deletion:

sudo ufw status numbered
sudo ufw delete 3

Replace 3 with the actual rule number you want to remove.

For a full reference on UFW commands, check the official Ubuntu UFW documentation.

Troubleshooting Common UFW Firewall Issues on Ubuntu 24.04

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’re on a cloud server, use the provider’s web console to access your machine. Then run:

sudo ufw allow ssh
sudo ufw reload

Problem: UFW is active but traffic isn’t being blocked

Check whether another firewall tool like iptables is overriding UFW. Run sudo iptables -L to inspect active rules. Also confirm UFW is set to start on boot:

sudo systemctl enable ufw

Problem: IPv6 rules aren’t applying

Open the UFW configuration file and make sure IPv6 is enabled.

sudo nano /etc/default/ufw

Find the line IPV6=yes and confirm it’s set to yes. Save the file, then reload UFW:

sudo ufw reload

Problem: A specific application isn’t connecting

Check whether the port is actually open using:

sudo ufw status | grep PORT_NUMBER

Replace PORT_NUMBER with the port you’re checking. If it’s missing, add the rule and reload.

You can find more detail on Linux firewall management in the DigitalOcean UFW Essentials guide, which covers advanced rule scenarios in depth.

Conclusion

You now know how to configure UFW firewall on Ubuntu 24.04 to secure your server from unauthorized access. You’ve set default deny policies, opened only the ports your server needs, and verified your rules are active. These steps form the foundation of any solid server security setup.

From here, consider exploring fail2ban to block brute-force SSH attempts. You should also review your open ports regularly as your server’s role changes. Keeping your firewall rules clean and minimal reduces your attack surface significantly.

For WordPress servers specifically, you only need ports 22, 80, and 443 open in most cases. Keep your rules simple. The fewer open ports you have, the less exposure your server has to potential threats.

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