Although it seems that Plesk 7.5.4 for Unix/Linux is almost compatible with MySQL 4.1.x, there is one problem with the PHP 4.x.x series, that still uses the old MySQL 3.23.x libraries to interface to MySQL. If you have the above scenario on your server you have to set MySQL 4.1.x to use the old password format or you will receive an error along the lines of:
Error (1251) : Client does not support authentication protocol requested by
server; consider upgrading MySQL client.
Adding the entry below to the
[mysqld] section of your
/etc/my.cnf file solves the problem: