No one at the company knew why the file had appeared. The monitoring logs showed only a brief TCP handshake from an IP that resolved to nothing, a ghost with polite manners. The file's size was unremarkable — 1.37 GB — but its checksum refused to match anything in the database. It was, by every metric, ordinary and impossible.
location /media/mkv/ valid_referers none blocked myserver.com *.myserver.com; if ($invalid_referer) return 403; myservercom filemkv