http_host_proxy.patch

gistfile1.php

diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 80b6eb1..5b28e98 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -333,7 +333,15 @@ function conf_path($require_settings = TRUE, $reset = FALSE) {
 
   $confdir = 'sites';
   $uri = explode('/', $_SERVER['SCRIPT_NAME'] ? $_SERVER['SCRIPT_NAME'] : $_SERVER['SCRIPT_FILENAME']);
-  $server = explode('.', implode('.', array_reverse(explode(':', rtrim($_SERVER['HTTP_HOST'], '.')))));
+
+  // Special reverse proxy patch to allow prserve original HTTP_HOST header
+  // but load correct settings.php file
+  $settingsHeader = $_SERVER['HTTP_HOST'];
+  if (isset($_SERVER['HTTP_HOST_PROXY'])) {
+    $settingsHeader = $_SERVER['HTTP_HOST_PROXY'];
+  }
+
+  $server = explode('.', implode('.', array_reverse(explode(':', rtrim($settingsHeader, '.')))));
   for ($i = count($uri) - 1; $i > 0; $i--) {
     for ($j = count($server); $j > 0; $j--) {
       $dir = implode('.', array_slice($server, -$j)) . implode('.', array_slice($uri, 0, $i));