Why Does My Remote MySQL Connection Fail with 'Unknown Authentication Method'?

Remote MySQL Connection Fails with "Unknown Authentication Method"

When attempting to establish a remote connection to a MySQL server, the dreaded "unknown authentication method" error can be encountered. This issue arises when the server's authentication mechanism is incompatible with the client's.

In this particular case, the error was encountered when connecting from a local machine (MySQL version 5.5.27) to a remote server (MySQL version 5.5.23). The underlying cause was the incompatibility between the password hash methods used by the two servers.

Resolving the Incompatibility

The solution to this problem is to update the password hash on the server to match the method used by the client. In this instance, it involves updating to the newer 41-byte password format employed by MySQL 4.1 and later.

Updating the Password Hash

• Log into the remote MySQL server using a command-line tool such as MySQL Workbench.
• Execute the following command:

ALTER USER 'yourusername'@'%' IDENTIFIED BY 'new_password';

where 'yourusername' is your MySQL username and 'new_password' is your new password.

• Flush the privileges to apply the changes:

FLUSH PRIVILEGES;

Restart the MySQL server to ensure the changes take effect.

Modifying Client Code

Once the password has been updated, modify your connection code as follows:

$dsn = 'mysql:host=184.173.209.193;dbname=my_db_name;charset=utf8';
$options = array(
    PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
    PDO::MYSQL_ATTR_DIRECT_QUERY => true
);

try {
    $online_dbh = new PDO($dsn, 'myusername', 'new_password', $options);
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Congratulations!";
} catch (PDOException $e) {
    echo $e->getMessage();
}

Setting PDO::MYSQL_ATTR_DIRECT_QUERY to true forces PDO to use the more secure connection method, resolving the authentication issue.

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