The X-Forwarded-For (XFF) request header is a de-facto standard header for
identifying the originating IP address of a client connecting to a web server through a proxy server.
The X-Forwarded-Host (XFH) header is a de-facto standard header for identifying the
original host requested by the client in the Host HTTP request header.
The X-Forwarded-Proto (XFP) header is a de-facto standard header for
identifying the protocol (HTTP or HTTPS) that a client used to connect to your proxy or load balancer.