Hello,
I have a setup where I am utilizing the notify_url variable in subscription buttons to register clients with my custom CMS. Currently it is simply accepting the POST transaction through an ASP page that processes the information. Does PayPal provide a way to securely verify that these POST transactions are valid and coming from PayPal? Or is there another way to validate the data so it accepts the PayPal POST and rejects all others? Thank you in advance.
-Dean