Added support for standard Forwarded header

Refs symfony/symfony#11379

Author: tony-co

cookbook/request/load_balancer_reverse_proxy.rst

@@ -7,9 +7,11 @@ an AWS Elastic Load Balancer) or a reverse proxy (e.g. Varnish for
 
 For the most part, this doesn't cause any problems with Symfony. But, when
 a request passes through a proxy, certain request information is sent using
-special ``X-Forwarded-*`` headers. For example, instead of reading the ``REMOTE_ADDR``
-header (which will now be the IP address of your reverse proxy), the user's
-true IP will be stored in an ``X-Forwarded-For`` header.
+either the standard ``Forwarded`` header or non standard special ``X-Forwarded-*``
+headers. For example, instead of reading the ``REMOTE_ADDR`` header (which
+will now be the IP address of your reverse proxy), the user's true IP will be
+stored in a standard ``Forwarded: for="..."`` header or a non standard
+``X-Forwarded-For`` header.
 
 If you don't configure Symfony to look for these headers, you'll get incorrect
 information about the client's IP address, whether or not the client is connecting
@@ -57,9 +59,9 @@ the IP address ``192.0.0.1`` or matches the range of IP addresses that use
 the CIDR notation ``10.0.0.0/8``. For more details, see the
 :ref:`framework.trusted_proxies <reference-framework-trusted-proxies>` option.
 
-That's it! Symfony will now look for the correct ``X-Forwarded-*`` headers
-to get information like the client's IP address, host, port and whether or
-not the request is using HTTPS.
+That's it! Symfony will now look for the correct headers to get information
+like the client's IP address, host, port and whether or not the request is
+using HTTPS.
 
 But what if the IP of my Reverse Proxy Changes Constantly!
 ----------------------------------------------------------
@@ -90,9 +92,15 @@ other information.
 My Reverse Proxy Uses Non-Standard (not X-Forwarded) Headers
 ------------------------------------------------------------
 
-Most reverse proxies store information on specific ``X-Forwarded-*`` headers.
-But if your reverse proxy uses non-standard header names, you can configure
+Although `rfc7239`_ recently defined a standard ``Forwarded`` header to disclose
+all proxy information, most reverse proxies stores information on non standard
+``X-Forwarded-*`` headers.
+But if your reverse proxy uses other non-standard header names, you can configure
 these (see ":doc:`/components/http_foundation/trusting_proxies`").
 The code for doing this will need to live in your front controller (e.g. ``web/app.php``).
 
+.. versionadded:: 2.6
+    ``Forwarded`` header support was introduced in Symfony 2.6
+
 .. _`security groups`: http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/using-elb-security-groups.html
+.. _`rfc7239`: http://tools.ietf.org/html/rfc7239