diff --git a/src/applications/diffusion/controller/DiffusionSymbolController.php b/src/applications/diffusion/controller/DiffusionSymbolController.php
index 16635c708b..7267ab849e 100644
--- a/src/applications/diffusion/controller/DiffusionSymbolController.php
+++ b/src/applications/diffusion/controller/DiffusionSymbolController.php
@@ -57,6 +57,7 @@ final class DiffusionSymbolController extends DiffusionController {
           $functions = get_defined_functions();
           if (in_array($this->name, $functions['internal'])) {
             return id(new AphrontRedirectResponse())
+              ->setIsExternal(true)
               ->setURI('http://www.php.net/function.'.$this->name);
           }
         }
@@ -65,6 +66,7 @@ final class DiffusionSymbolController extends DiffusionController {
               interface_exists($this->name, false)) {
             if (id(new ReflectionClass($this->name))->isInternal()) {
               return id(new AphrontRedirectResponse())
+                ->setIsExternal(true)
                 ->setURI('http://www.php.net/class.'.$this->name);
             }
           }