trusting_proxies.rst

.. index::
   single: Request; Trusted Proxies

Trusting Proxies

If you find yourself behind some sort of proxy - like a load balancer - then certain header information may be sent to you using special X-Forwarded-* headers. For example, the Host HTTP header is usually used to return the requested host. But when you're behind a proxy, the true host may be stored in a X-Forwarded-Host header.

Since HTTP headers can be spoofed, Symfony2 does not trust these proxy headers by default. If you are behind a proxy, you should manually whitelist your proxy.

.. versionadded:: 2.3
    CIDR notation support was introduced, so you can whitelist whole
    subnets (e.g. ``10.0.0.0/8``, ``fc00::/7``).

use Symfony\Component\HttpFoundation\Request;

$request = Request::createFromGlobals();

// only trust proxy headers coming from this IP addresses
$request->setTrustedProxies(array('192.0.0.1', '10.0.0.0/8'));

Configuring Header Names

By default, the following proxy headers are trusted:

• X-Forwarded-For Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getClientIp`;
• X-Forwarded-Host Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getHost`;
• X-Forwarded-Port Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getPort`;
• X-Forwarded-Proto Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getScheme` and :method:`Symfony\\Component\\HttpFoundation\\Request::isSecure`;

If your reverse proxy uses a different header name for any of these, you can configure that header name via :method:`Symfony\\Component\\HttpFoundation\\Request::setTrustedHeaderName`:

$request->setTrustedHeaderName(Request::HEADER_CLIENT_IP, 'X-Proxy-For');
$request->setTrustedHeaderName(Request::HEADER_CLIENT_HOST, 'X-Proxy-Host');
$request->setTrustedHeaderName(Request::HEADER_CLIENT_PORT, 'X-Proxy-Port');
$request->setTrustedHeaderName(Request::HEADER_CLIENT_PROTO, 'X-Proxy-Proto');

Not trusting certain Headers

By default, if you whitelist your proxy's IP address, then all four headers listed above are trusted. If you need to trust some of these headers but not others, you can do that as well:

// disables trusting the ``X-Forwarded-Proto`` header, the default header is used
$request->setTrustedHeaderName(Request::HEADER_CLIENT_PROTO, '');