UPDATE 1:
According to this tutorial on Using PayPal\'s Instant Payment Notification with PHP, PayPal cannot access locally hosted websites unless c
One simple solution is described in the official developers page of PayPal:
developer.paypal.com - Local IPN Testing
The trick consists on writing a small HTML file with this content:
To get the real results you need to copy all of the IPN variables which PayPal sends. These real variables can be found into the PayPal account, under IPN History:
IPNs History
You need to click on the relative Message ID and then copy the "IPN Message" content (it will be something like mc_gross=27.00&invoice=Test-1&protection_eligibility=Ineligible&...) which must be converted into HTML hidden input fields. For example:
....
After setting up all of these variables and changing the action URL, you can open the file with a browser and then submit this form.