Handle PayPal return with Request.UrlReferrer

 Hi,
 In my asp.net site, I use the 'PayPal Buy Now Button', after the buyer is redirected to the paypal page and accept money, he's redirected again to the page(My Site) from where the order has been done. In that moment, I'll have to handle properly and to send mail to the user with link for downloading of the program.
 
Is it good idea to check  with Request.UrlReferrer that user is redirected from paypal to the order page ?
 
Thanks in advance,
Tihomir Ivanov

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