How to Fix the 'Cannot connect to MySQL 4.1 using old authentication' Error in PHP?

Connecting to MySQL 4.1 : Troubleshooting "Cannot connect to MySQL 4.1 using old authentication" Error

When attempting to establish a connection to a MySQL database using MySQLi in PHP 5.3, you may encounter the error message "Connect Error (2000) mysqlnd cannot connect to MySQL 4.1 using old authentication." This error typically arises when the MySQL server is configured to utilize an outdated password schema that is no longer compatible with newer MySQL versions.

To resolve this issue, there are several steps that can be taken:

1. Verify MySQL Configuration:

   • Run the SQL query SHOW VARIABLES LIKE 'old_passwords' to determine if the server is using the old password schema. If the result is old_passwords,Off, it indicates that the server is not using the old schema, and the error may be related to specific user accounts.

2. Check User Passwords:

   • Use the query SELECT *User*', Host', Length(Password) FROM mysql.user to examine the mysql.user` table.
   • Accounts using old passwords will have password lengths of 16, while those using new passwords will have lengths of 41.

3. Reset User Passwords:

   • If old passwords are detected, reset the passwords for the affected accounts using the following query:

     • SET PASSWORD FOR 'User'@'Host'=PASSWORD('yourpassword');
     • Replace User and Host with the values obtained from the previous query.

4. Flush Privileges:

   • Execute the query FLUSH Privileges; to ensure that the changes to user passwords take effect.

5. Recheck Password Length:

   • Run the same query (SELECT *User*', Host', Length(Password) FROM mysql.user`) again to verify that the password lengths for the affected accounts are now 41.

6. Connect with MySQLi:

   • Once the user passwords have been updated to use the new schema, attempt to connect to the database using MySQLi.

By following these steps, you can troubleshoot the "Cannot connect to MySQL 4.1 using old authentication" error and establish a successful connection to your MySQL database. Refer to the MySQL documentation for additional details on old and new password hashing methods, password management, and server configuration.

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