PHP HTTP Referrer

Question

I have a page which accepts POSTs from a remote site. I would like to detect the domain that these POSTs are coming from. I realize that it can be spoofed but it is better than nothing. I have tried accessing the HTTP_REFERER variable but it just returns null.

The page accepts POSTs from sources like PayPal (instant payment notifications) and other payment gateways.

How can I get the referring call?

Answer 1

You spelled Referer correctly. It should be:

$_SERVER['HTTP_REFERER']

Answer 2

$_SERVER['HTTP_REFERER'] 

with a single R, try var_dump($_SERVER) for more info.