diff --git a/core/mappings.js b/core/mappings.js
index 32d63d8ba31e8f01ad43c09ccae1fd88b01031d3..63de82dfe97ee2072e72cbe6c256e54854d9d9cb 100644
--- a/core/mappings.js
+++ b/core/mappings.js
@@ -237,3 +237,6 @@ var mappings = {
         }
     }
 };
+
+// Mirror
+mappings['ajax.proxy.ustclug.org'] = mappings['ajax.googleapis.com'];