Hi, we are implementing Transparent Redirect wih Payflow Pro. For this implementation, we receive postbacks on the return URL and error data on the error URL if a transaction fails. I would like to know the best practices to secure these URLs to prevent unauthorized posts. Specifically, are there recommended methods, such as validating the REMOTE_ADDR, to ensure that the requests are only coming from PayPal’s servers (in the context of an ASP.NET application)?
