Why is mysqli_connect Failing with 'authentication method unknown to the client [caching_sha2_password]' and How Can I Fix It?

Overcoming Authentication Challenges in mysqli_connect

The mysqli_connect function facilitates database connections in PHP. However, when attempting to connect to a MySQL database using caching_sha2_password authentication, users may encounter authentication issues. This article explores the root cause and offers a solution to this problem.

The Issue

In the provided code snippet, the default_authentication_plugin setting in the MySQL Server ini file is set to caching_sha2_password. This configuration prevents users from authenticating with usernames that do not have a corresponding caching_sha2_password. As a result, the error message "The server requested authentication method unknown to the client [caching_sha2_password]" is displayed.

The Solution

To resolve this issue, you can either:

• Change the default_authentication_plugin setting:

  • Set it to mysql_native_password to allow user1 to log in but not user2.

• Modify User Authentication:

  • Use the ALTER USER SQL command to change the password for user1 and user2 to be compatible with caching_sha2_password:

    • For existing users:

      • ALTER USER 'mysqlUsername'@'localhost' IDENTIFIED WITH mysql_native_password BY 'mysqlUsernamePassword';

    • For new users:

      • CREATE USER 'jeffrey'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

Implementation

After modifying the authentication plugin setting or user passwords, the mysqli_connect code will successfully establish a connection to the MySQL database.

Conclusion

By understanding the underlying authentication issue and implementing either of the provided solutions, you can overcome the "authentication method unknown to the client" error when using mysqli_connect with caching_sha2_password authentication.

The above is the detailed content of Why is mysqli_connect Failing with 'authentication method unknown to the client [caching_sha2_password]' and How Can I Fix It?. For more information, please follow other related articles on the PHP Chinese website!