How to Fix \"mysqlnd cannot connect to MySQL 4.1 using old authentication\" Error?

MySQL Connectivity Error with Old Authentication

Encountering the error message "mysqlnd cannot connect to MySQL 4.1 using old authentication" signifies a compatibility issue when attempting to connect to a MySQL database that utilizes an outdated password scheme. To resolve this problem, it's crucial to determine if the database server is configured to use the old password schema.

Checking the Server Configuration

Execute the following SQL query:

<code class="sql">SHOW VARIABLES LIKE 'old_passwords'</code>

Understanding the Results

• If the result is old_passwords,Off, the server is configured to use the new authentication routine. User passwords may be stored in the old format, but the server will use the new routine for authentication.
• If the result is old_passwords,On, the server is configured to use the old authentication routine by default. In this case, the old password scheme is used for authentication.

Troubleshooting and Resolution

To resolve the issue, follow these steps:

1. Check User Password Format: Verify the user's password length in the mysql.user table. A length of 16 characters indicates an old password, while a length of 41 characters signifies a new password.
2. Set a New Password (if necessary): If the user's password is in the old format, set a new password using the following command:

<code class="sql">SET PASSWORD FOR 'User'@'Host'=PASSWORD('yourpassword');</code>

3. Flush Privileges: Update the database's privileges by executing:

<code class="sql">FLUSH Privileges;</code>

4. Reverify Password Length: Check the user's password length again in the mysql.user table. It should now be 41 characters, indicating that the new password format is being used.
5. Recreate Connection: After completing these steps, try reconnecting to the database with your client (e.g., mysqlnd). The connection should succeed.

Additional Resources

For further information, refer to the following MySQL documentation:

• http://dev.mysql.com/doc/refman/5.0/en/old-client.html
• http://dev.mysql.com/doc/refman/5.0/en/password-hashing.html
• http://dev.mysql.com/doc/refman/5.0/en/set-password.html

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