Yes. One can identify the IP address of the origin server behind a reverse proxy if the server responds to direct requests in a way that identifies itself. See:

Yes. One can identify the IP address of the origin server behind a reverse proxy if the server responds to direct requests in a way that identifies itself. See: https://cloudpiercer.org/ https://cloudpiercer.org/ Two steps towards obscuring the origin server include requiring that the HTTP Host header is set and only responding to Cloudflare IP ranges: https://www.cloudflare.com/ips/ https://www.cloudflare.com/ips/