80% of Our Web Traffic Was a Dead Subdomain Redirecting to Itself
Aprimerose sells infrastructure to companies that have to prove where their data goes. On 17 October we looked at our own website’s traffic properly for the first time in a long while. Cloudflare’s seven-day view showed 230,680 requests. 200,170 of them were 301 redirects. 186,270 had no user agent. 185,560 were for a single hostname: app.aprimerose.com. That hostname pointed at a Firebase app that no longer existed. Over HTTPS, Firebase answered “Site Not Found”. Over plain HTTP, it redirected to HTTPS. Cloudflare was set to reach origin servers over plain HTTP, so it fetched the HTTP version, got the redirect, and handed it to the visitor, who asked for the HTTPS address and got the same redirect again. The address redirected to itself. A client that follows redirects makes a chain of requests per attempt before it gives up (curl stopped at thirty), so one caller can look like many. The nine busiest client addresses, half of the week’s requests, belonged to Microsoft, and the top five countries (India, Australia, Korea, Hong Kong, Japan) match Azure regions. We never found out whose machines they were. ...