# X-Forwarded-Host header

The HTTP **`X-Forwarded-Host`** (XFH) [request header](https://developer.mozilla.org/en-US/docs/Glossary/request%20header) is a de-facto standard header for identifying the original host requested by the client in the [Host](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Host) HTTP request header.

Host names and ports of reverse [proxies](https://developer.mozilla.org/en-US/docs/Glossary/Proxy_server) (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 [Forwarded](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Forwarded) header, although it's much less frequently used.

<table class="properties">
  <tbody>
    <tr>
      <th scope="row">Header type</th>
      <td>[Request header](https://developer.mozilla.org/en-US/docs/Glossary/Request%20header)</td>
    </tr>
    <tr>
      <th scope="row">[Forbidden request header](https://developer.mozilla.org/en-US/docs/Glossary/Forbidden%20request%20header)</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

- [X-Forwarded-For](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For), [X-Forwarded-Proto](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto) headers
- [Host](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Host)
- [Forwarded](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Forwarded)