How to open TCP port 3306 in ubuntu 25.04

If you’re running MySQL or MariaDB on Ubuntu 25.04 and want to allow external access, you’ll need to open TCP port 3306.

Step 1: Make Sure UFW is Installed

Ubuntu includes UFW by default, but if it’s missing, install it:

sudo apt update
sudo apt install ufw

Check its status:

sudo ufw status

If it says “inactive”, move to the next step to enable it.

Step 2: Enable UFW

Enable the firewall (if it’s not already active):

sudo ufw enable

This will start UFW without interrupting current SSH or other active sessions.

Step 3: Open Port 3306 for TCP

To allow incoming MySQL/MariaDB connections on port 3306:

sudo ufw allow 3306/tcp

This opens the port for all external IPs. To limit access to a specific IP (e.g., 192.168.1.50), use:

sudo ufw allow from 192.168.1.50 to any port 3306 proto tcp

Step 4: Verify the Rule

Check if the rule was added:

sudo ufw status numbered

You should see a rule allowing TCP traffic on port 3306.

Step 5: Ensure MySQL is Listening on External IPs

Open MySQL config file:

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf

Find the line:

bind-address = 127.0.0.1

Change it to:

bind-address = 0.0.0.0

Save and exit. Then restart MySQL:

sudo systemctl restart mysql