[PHP-WIN] HTTP Header REFERER

[Randall Barber]

In apache, the variable:

HTTP_REFERER is automatically set.

I don't run apache, I tried to access the variable like this in a regular script:

<?php

echo "$http_referer";

?>

Other variations include:

$HTTP_REFERER

$HTTP_X_REFERER

$myVar = getenv("HTTP_REFERER");

I don't get that variable.  All the mail I found in the archives says:

$HTTP_REFERER

It is not working for me.  

Please tell me what I am missing here.  I thought that all values of an HTTP header 
were passed to PHP.  Does that not include a HTTP REQUEST header field REFERRER?

I run NT4.0 IIS.

Thanks in advance
RDB