diff --git a/cookbook/cache/varnish.rst b/cookbook/cache/varnish.rst
index e461e3124ee..0ad665ca938 100644
--- a/cookbook/cache/varnish.rst
+++ b/cookbook/cache/varnish.rst
@@ -176,5 +176,29 @@ that will invalidate the cache for a given resource:
             }
         }
 
+Routing
+------------------
+
+To ensure that the Symfony Router generates urls correctly with Varnish,
+proper ```X-Forwarded``` headers must be added. Headers depend on how you
+have configured hosts and ports for the web server and Varnish but this
+example should work if the web server is using the same IP as Varnish but
+a different port (e.g. 8080).
+
+.. code-block:: text
+
+    sub vcl_recv {
+        if (req.http.X-Forwarded-Proto == "https" ) {
+            set req.http.X-Forwarded-Port = "443";
+        } else {
+            set req.http.X-Forwarded-Port = "80"
+        }
+    }
+
+.. note::
+
+    Remember to set ``framework.trust_proxy_headers: true`` in the Symfony
+    configuration for this to work.
+
 .. _`Edge Architecture`: http://www.w3.org/TR/edge-arch
 .. _`GZIP and Varnish`: https://www.varnish-cache.org/docs/3.0/phk/gzip.html