diff --git a/lib/http-proxy/passes/web-incoming.js b/lib/http-proxy/passes/web-incoming.js
index 995a0db4d..781b32692 100644
--- a/lib/http-proxy/passes/web-incoming.js
+++ b/lib/http-proxy/passes/web-incoming.js
@@ -82,7 +82,7 @@ module.exports = {
         values[header];
     });
 
-    req.headers['x-forwarded-host'] = req.headers['host'] || '';
+    req.headers['x-forwarded-host'] = req.headers['x-forwarded-host'] || req.headers['host'] || '';
   },
 
   /**