mysqlnd cannot connect to MySQL 4.1+ using the old insecure

文章介绍了关于mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication方法，有需要了解的同学可参考一下。

Warning: mysql_connect() [.mysql-connect]: Premature end of data (mysqlnd_wireprotocol.c:554) in path/to/the/file/where/connection/script/is/written/

Warning: mysql_connect() [function.mysql-connect]: OK packet 1 bytes shorter than expected in path/to/the/file/where/connection/script/is/written/

Warning: mysql_connect() [function.mysql-connect]: mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your pass with the command SET PASSWORD = PASSWORD('your_existing_password'). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file in path/to/the/file/where/connection/script/is/written/

1. Change MySQL to NOT to use old_passwords
It seems that even MySQL 5.x versions still default to the old password hashes. You need to change this in “my.cnf” (e.g. /etc/my.cnf): remove or comment out the line that says
old_passwords = 1
 //
old_passwords = 1为16位
//所以这里要先
/
/SET old_passwords = 0;
//这样使新密码的长度也变成41位
Restart MySQL. If you don’t, MySQL will keep using the old password format, which will mean that you cannot upgrade the passwords using the builtin PASSWORD() hashing function. You can test this by running:

具体原因我还不是很清楚，跟old密码长度有关？先记录下来，日后研究。解决方法如下：

附 PHP连接MySQL测试代码：