Unknown MySQL Server Host 127.0 0.1 3306 – A Complete Guide for Devs

Hello Dev, are you struggling with the error “Unknown MySQL Server Host 127.0 0.1 3306” while working on your project? No need to worry, as you have come to the right place. In this article, we will provide you with a complete guide to understand this error and learn how to fix it.

What is “Unknown MySQL Server Host 127.0 0.1 3306” Error?

The error “Unknown MySQL Server Host 127.0 0.1 3306” occurs when a connection between your project and the MySQL server is denied. The numbers mentioned in the error usually signify the host IP address and port number.

This error can occur due to various reasons like incorrect MySQL server configuration, incorrect hostname, incorrect username or password, issues with the firewall, etc.

What are the Symptoms of “Unknown MySQL Server Host 127.0 0.1 3306” Error?

The error message “Unknown MySQL Server Host 127.0 0.1 3306” is displayed on the screen when trying to connect to the MySQL server. In some cases, the error message can be different, but it signifies the same problem.

The error can also cause issues in the functionality of your application, as it fails to connect with the database.

What are the Causes of “Unknown MySQL Server Host 127.0 0.1 3306” Error?

The following are some common causes of the “Unknown MySQL Server Host 127.0 0.1 3306” error:

How to Fix “Unknown MySQL Server Host 127.0 0.1 3306” Error?

Check MySQL Server Configuration

The first and foremost step is to check if the MySQL server is configured correctly. Ensure that the hostnames, usernames, and passwords are correct. Also, check if the port number is correct. The default port for MySQL is 3306.

You can check the MySQL configuration file located at /etc/mysql/my.cnf (if using Linux) or C:\ProgramData\MySQL\MySQL Server 8.x\my.ini (if using Windows).

Check Firewall Settings

If the firewall settings are blocking connections between the application and the MySQL server, then you need to add an exception to allow the application to connect with the MySQL server.

In Linux, you can use the following command to allow connections on port 3306:

sudo ufw allow 3306/tcp

In Windows, you can add an inbound rule to allow connections on port 3306 for the MySQL server.

Check Hostname

If the hostname provided is incorrect, then the application will not be able to connect with the MySQL server. Ensure that the hostname mentioned in the configuration file is correct.

Check if MySQL Server is Running

If the MySQL server is not running, then the application will not be able to connect with it. Ensure that the MySQL server is running.

You can check if the MySQL server is running in Linux using the following command:

sudo systemctl status mysql

You can check if the MySQL server is running in Windows using the Services panel.

FAQs

1. What does “Unknown MySQL Server Host 127.0 0.1 3306” mean?

The error “Unknown MySQL Server Host 127.0 0.1 3306” occurs when the application is unable to connect with the MySQL server due to various reasons like incorrect configuration, firewall issues, incorrect hostname, etc.

2. How to resolve “Unknown MySQL Server Host 127.0 0.1 3306” error?

To resolve this error, you need to check the MySQL server configuration, firewall settings, hostname, and if the MySQL server is running or not.

3. What is the default port for MySQL?

The default port for MySQL is 3306.

4. How to check if the MySQL server is running?

You can check if the MySQL server is running in Linux using the following command:

sudo systemctl status mysql

You can check if the MySQL server is running in Windows using the Services panel.

5. How to allow connections on port 3306?

In Linux, you can use the following command to allow connections on port 3306:

sudo ufw allow 3306/tcp

In Windows, you can add an inbound rule to allow connections on port 3306 for the MySQL server.

That’s it, Dev! We hope this article helped you in understanding the “Unknown MySQL Server Host 127.0 0.1 3306” error and how to fix it. If you have any queries or suggestions, feel free to leave a comment below.