I don't think we do, but that's a good idea! I think it could be automatic. We'd have to first detect that the origin server appears to be blocking non-Cloudfla

I don't think we do, but that's a good idea! I think it could be automatic. We'd have to first detect that the origin server appears to be blocking non-Cloudflare IPs, by seeing if it responds to requests from some random non-CF IP address. Then we'd verify that it refuses to respond to a request for some dummy domain. If it serves the site's normal content when the host name is from the wrong domain, then we could alert the customer that they seem to have an insecure configuration. I will suggest this internally...