URL checker for page access

I have a page on my site that is reached after someone has made a payment from one of a couple of payment sites. What I need is a snippet of code written in ColdFusion that checks what URL a visiter is coming from. If the visitor is trying to access the page from anywhere but a predetermined URL then they are denied access to the web page. This should be a simple undertaking. I would like to specify which URLs so please keep the code generic and comment where I need to put the refering URLs in place. I would also like a piece of code written that will prevent someone from accessing a page by hitting the back button. In other words I would like to make a page that is both inaccessible from anywhere except those pages or sites that I allow and also from hitting the back button. I DO NOT want this written in javascript because all someone would need to do is turn off the javascript on their browser. So please present this in ColdFusion ONLY and comment the code well. Thanks! ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Complete ownership and distribution copyrights to all work purchased. ## Platform Web Browsers, ColdFusion, Access