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X-Forwarded-Host header

files/en-us/web/http/reference/headers/x-forwarded-host/index.md

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The HTTP X-Forwarded-Host (XFH) {{Glossary("request header")}} is a de-facto standard header for identifying the original host requested by the client in the {{HTTPHeader("Host")}} HTTP request header.

Host names and ports of reverse {{Glossary("Proxy_server", "proxies")}} (load balancers, CDNs) may differ from the origin server handling the request, in that case the X-Forwarded-Host header is useful to determine which Host was originally used.

A standardized version of this header is the HTTP {{HTTPHeader("Forwarded")}} header, although it's much less frequently used.

<table class="properties"> <tbody> <tr> <th scope="row">Header type</th> <td>{{Glossary("Request header")}}</td> </tr> <tr> <th scope="row">{{Glossary("Forbidden request header")}}</th> <td>No</td> </tr> </tbody> </table>

Syntax

http
X-Forwarded-Host: <host>

Directives

  • <host>
    • : The domain name of the forwarded server.

Examples

http
X-Forwarded-Host: id42.example-cdn.com

Specifications

Not part of any current specification.

See also

  • {{HTTPHeader("X-Forwarded-For")}}, {{HTTPHeader("X-Forwarded-Proto")}} headers
  • {{HTTPHeader("Host")}}
  • {{HTTPHeader("Forwarded")}}