I am certain there are a few caveats to this solution (i.e. disorders less than which Referer is not really despatched, potential for being spammed by way of bogus Referer URLs), but I can't speak to all of them. The Wikipedia webpage could be a very good start line. EDIT: https://ricardoyhpwb.ja-blog.com/34247721/the-definitive-guide-to-devil-website