mysql_connect(): Client does not support authentication protocol requested by server; consider upgrading MySQL client

PHP can give you this error when trying to connect to an mysql database.
To solve this problem run the mySql command line client and enter the following command:
SET PASSWORD FOR 'user'@'host' = OLD_PASSWORD('password');

example:
my user: is peter, my password: something and my host: localhost
the command will be:

SET PASSWORD FOR peter@localhost = OLD_PASSWORD('something');"