Regarding the 100TB of Access Denied pages: just drop the connection instead. To make the system more scalable: instead of directly serving the file, serve a b

Regarding the 100TB of Access Denied pages: just drop the connection instead. To make the system more scalable: instead of directly serving the file, serve a bunch of URLs to mirrors plus a checksum. The client must pick one of them. You can randomize the URLs and maybe add some geo logic to it. Let people provide mirrors. An additional indiraction step like this can prove incredibly powerful for systems that need to scale massively.