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Documented how to configure Symfony correctly with regards to the Forwarded header
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‎components/http_foundation/trusting_proxies.rst

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@@ -11,9 +11,9 @@ Trusting Proxies
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If you find yourself behind some sort of proxy - like a load balancer - then
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certain header information may be sent to you using special ``X-Forwarded-*``
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headers. For example, the ``Host`` HTTP header is usually used to return
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the requested host. But when you're behind a proxy, the true host may be
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stored in a ``X-Forwarded-Host`` header.
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headers or the ``Forwarded`` header. For example, the ``Host`` HTTP header is
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usually used to return the requested host. But when you're behind a proxy,
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the actual host may be stored in a ``X-Forwarded-Host`` header.
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Since HTTP headers can be spoofed, Symfony does *not* trust these proxy
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headers by default. If you are behind a proxy, you should manually whitelist
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// only trust proxy headers coming from this IP addresses
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Request::setTrustedProxies(array('192.0.0.1', '10.0.0.0/8'));
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You should also make sure that your proxy filters unauthorized use of these
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headers, e.g. if a proxy natively uses the ``X-Forwarded-For`` header, it
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should not allow clients to send ``Forwarded`` headers to Symfony.
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If your proxy does not filter headers appropriately, you need to configure
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Symfony not to trust the headers your proxy does not filter (see below).
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Configuring Header Names
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------------------------
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By default, the following proxy headers are trusted:
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* ``Forwarded`` Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getClientIp`;
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* ``X-Forwarded-For`` Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getClientIp`;
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* ``X-Forwarded-Host`` Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getHost`;
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* ``X-Forwarded-Port`` Used in :method:`Symfony\\Component\\HttpFoundation\\Request::getPort`;
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If your reverse proxy uses a different header name for any of these, you
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can configure that header name via :method:`Symfony\\Component\\HttpFoundation\\Request::setTrustedHeaderName`::
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Request::setTrustedHeaderName(Request::HEADER_FORWARDED, 'X-Forwarded');
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Request::setTrustedHeaderName(Request::HEADER_CLIENT_IP, 'X-Proxy-For');
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Request::setTrustedHeaderName(Request::HEADER_CLIENT_HOST, 'X-Proxy-Host');
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Request::setTrustedHeaderName(Request::HEADER_CLIENT_PORT, 'X-Proxy-Port');
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Not Trusting certain Headers
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----------------------------
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By default, if you whitelist your proxy's IP address, then all four headers
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By default, if you whitelist your proxy's IP address, then all five headers
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listed above are trusted. If you need to trust some of these headers but
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not others, you can do that as well::
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// disables trusting the ``X-Forwarded-Proto`` header, the default header is used
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Request::setTrustedHeaderName(Request::HEADER_CLIENT_PROTO, '');
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// disables trusting the ``Forwarded`` header
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Request::setTrustedHeaderName(Request::HEADER_FORWARDED, null);

‎cookbook/cache/varnish.rst

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@@ -24,6 +24,21 @@ Remember to configure :ref:`framework.trusted_proxies <reference-framework-trust
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in the Symfony configuration so that Varnish is seen as a trusted proxy and the
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:ref:`X-Forwarded <varnish-x-forwarded-headers>` headers are used.
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Varnish, in its default configuration, sends the ``X-Forwarded-For`` header but
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does not filter out the ``Forwarded`` header. If you have access to the Varnish
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configuration file, you can configure Varnish to remove the ``Forwarded``
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header:
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.. code-block:: varnish4
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sub vcl_recv {
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remove req.http.Forwarded;
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}
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If you do not have access to your Varnish configuration, you can instead
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configure Symfony to distrust the ``Forwarded`` header as detailed in
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:ref:`the cookbook <cookbook-request-untrust-header>`.
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.. _varnish-x-forwarded-headers:
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Routing and X-FORWARDED Headers

‎cookbook/request/load_balancer_reverse_proxy.rst

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@@ -23,7 +23,7 @@ via HTTPS, the client's port and the hostname being requested.
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Solution: trusted_proxies
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-------------------------
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This is no problem, but you *do* need to tell Symfony that this is happening
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This is no problem, but you *do* need to tell Symfony what is happening
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and which reverse proxy IP addresses will be doing this type of thing:
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.. configuration-block::
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the CIDR notation ``10.0.0.0/8``. For more details, see the
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:ref:`framework.trusted_proxies <reference-framework-trusted-proxies>` option.
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You are also saying that you trust that the proxy does not send conflicting
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headers, e.g. sending both X-Forwarded-For and Forwarded in the same request.
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That's it! Symfony will now look for the correct headers to get information
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like the client's IP address, host, port and whether the request is
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using HTTPS.
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If you allow outside traffic, they could "spoof" their true IP address and
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other information.
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.. _cookbook-request-untrust-header:
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My Reverse Proxy Sends X-Forwarded-For but does not Filter the Forwarded Header
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-------------------------------------------------------------------------------
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Many popular proxy implementations do not yet support the Forwarded header and
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do not filter it by default. Ideally, you would configure this
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in your proxy. If this is not possible, you can tell Symfony to distrust
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the Forwarded header, while still trusting your proxy's X-Forwarded-For header.
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This is done inside of your front controller::
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// web/app.php
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// ...
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Request::setTrustedHeaderName(Request::HEADER_FORWARDED, null);
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$response = $kernel->handle($request);
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// ...
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Configuring the proxy server trust is very important, as not doing so will
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malicious users to "spoof" their IP address.
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My Reverse Proxy Uses Non-Standard (not X-Forwarded) Headers
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------------------------------------------------------------
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