[thelist] http referrers?

[Sabrina Dent, Apperception]

More from the psycho-babble corner...

I have people completing a transaction on a PayPal server, and then they're
being returned to a specified .asp page on my site, post-transaction.  They
now need to download a PDF file off a link on this page.

How would I go about using http referrers (?) or anything really, to insure
that only requests coming from PayPal could open this page?  I'm not looking
for high-security here, just anything to make it "less easy."

Is there any way to protect that PDF file so it won't download on a direct
request?

Cheers,
Bri

<tip>
http://webservices.adobe.com/optimize/main.html

Very handy for quick optimising and transparencies.
</tip>