X-Forwarded-Proto
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. Your server access logs contain the protocol used between
the server and the load balancer, but not the protocol used between the client and the
load balancer. To determine the protocol used between the client and the load balancer,
the X-Forwarded-Proto request header can be used.
A standardized version of this header is the HTTP Forwarded header.
| Header type | Request header |
|---|---|
| Forbidden header name | no |
Syntax
http
X-Forwarded-Proto: <protocol>
Directives
- <protocol>
-
The forwarded protocol (http or https).
Examples
http
X-Forwarded-Proto: https
Other non-standard forms:
http
# Microsoft
Front-End-Https: on
X-Forwarded-Protocol: https
X-Forwarded-Ssl: on
X-Url-Scheme: https
Specifications
Not part of any current specification. The standardized version of this header is
Forwarded.