PayPal IPN Script not Redirecting to ipn.php

I have downloaded the sample paypal IPN script using php and customised with the email for the buyout option and it has also some hidden paramaters such amount, quantity,return_url, notify_url like this.After the success payment in the sandbox ur开发者_StackOverflow社区l,it doesn't redirect to the ipn.php to make database insertion for successful transaction.

My site url: http://anderson.000space.com/paypal_ipn/example-form.html

I have given the notify url for IPN in my paypal sandbox merchant account as http://anderson.000space.com/paypal_ipn/ipn.php. I have printed some values there and given exit in that page, but the redirection from paypal is not going to ipn.php.

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IPN is not the redirection page. "return" controls which page they're redirected back to, "notify_url" (IPN) is the script that receives a POST from PayPal with transaction information.