I am deploying my (PHP, MySQL) app on client local machine. For Expiry I am comparing current date with start date & End Date in DB. If current date is between start date & end date than fine go ahead, other wise user will not be able to login. How would user By PASS my app expiry logic. I need to know possible tricks where user can bypass my app so that I work on it and make expiry unbeatable. I need to know from where Apache is taking current date. if from OS then user can change it & bypass my app.
I think you are looking for: date_default_timezone_set ( string $timezone_identifier )
http://php.net/manual/en/function.date-default-timezone-set.php
You can also set this in your php.ini config.