What's a good way to determine where POST information was sent from
<p>I am writing a Instant Payment Notifications script for paypal in PHP. There are going to be other payment processors down the road, but they're going to be handled by the same function.</p>

<p>So I need to find a good way to detect where the post information came from.</p>

<p>Anyone have any experience handling paypal responses that could offer a suggestion?</p>
