MySQL connection refused, how to solve it?

MySQL connection refused, how to solve it?

When developing and using MySQL database, sometimes you will encounter the problem of connection refused. This can be due to a variety of reasons, such as a wrong username or password, network connection failure, and MySQL server misconfiguration. In this article, we will explore some possible solutions to resolve MySQL connection refused issue.

First, we need to confirm whether the MySQL server is running. This can be verified by trying to connect to the MySQL server. In a terminal or command prompt, enter the following command:

mysql -u用户名 -p密码 -h主机地址

Please replace "username" with your MySQL username, "password" with your MySQL password, and "host address" for your MySQL server address. If the connection is successful, you should be able to see the MySQL server's welcome message. If the connection is refused, you will need to continue trying other solutions.

Secondly, you need to check the settings of the MySQL server. Please ensure that the MySQL server allows remote connections and that the firewall is configured correctly. These settings can usually be found in the MySQL server's configuration file. For example, on Ubuntu, the MySQL configuration file is located at /etc/mysql/mysql.conf.d/mysqld.cnf. Make sure the following settings are configured correctly:

bind-address = 0.0.0.0

This will allow the MySQL server to accept connection requests from all IP addresses.

Similarly, on the MySQL server, you also need to confirm that the correct user and password for the connection have been created and that the user has been granted the necessary permissions. A new user and password can be created on the MySQL server using the following command:

CREATE USER '用户名'@'%' IDENTIFIED BY '密码';
GRANT ALL PRIVILEGES ON *.* TO '用户名'@'%';
FLUSH PRIVILEGES;

Make sure to replace "Username" and "Password" with the values ​​you set and use the appropriate permissions. This will grant this user permissions for all operations on all databases and tables.

If none of the above steps solve the problem, you can also try restarting the MySQL server and network device and ensure that the network connection is normal. Sometimes, a connection refused may be caused by a network failure or an unstable server.

Also, you can try more advanced tools to detect and troubleshoot connection issues. For example, you can use the telnet command to check whether the MySQL server's port is available. In a terminal or command prompt, enter the following command:

telnet 主机地址 端口号

Please replace "host address" with your MySQL server address and "port number" with the port number of your MySQL server (default is 3306) . If the connection is successful, you will see MySQL-related information. If the connection is refused or times out, there is a connection problem.

To summarize, when solving the MySQL connection refused problem, we should first check whether the MySQL server is running, and then ensure that the firewall and network settings are configured correctly. You also need to ensure that the correct user and password are created and assigned the appropriate permissions. When solving problems, we can also use advanced tools such as telnet for further diagnosis.

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