diff --git a/gns3server/modules/base.py b/gns3server/modules/base.py
index b62213af..f9c19ca0 100644
--- a/gns3server/modules/base.py
+++ b/gns3server/modules/base.py
@@ -159,7 +159,7 @@ class IModule(multiprocessing.Process):
             if signum:
                 self._ioloop.add_callback_from_signal(self._shutdown)
             else:
-                self._shutdown()
+                self._ioloop.add_callback(self._shutdown)
 
     def send_response(self, results):
         """
@@ -240,6 +240,13 @@ class IModule(multiprocessing.Process):
         if self._stopping:
             return
 
+        # handle special request to stop the module
+        # e.g. useful on Windows where the
+        # SIGBREAK signal cound't be propagated
+        if request[0] == b"stop":
+            self.stop()
+            return
+
         try:
             request = zmq.utils.jsonapi.loads(request[0])
         except ValueError:
diff --git a/gns3server/modules/dynamips/__init__.py b/gns3server/modules/dynamips/__init__.py
index 62ea82c6..9cc3c752 100644
--- a/gns3server/modules/dynamips/__init__.py
+++ b/gns3server/modules/dynamips/__init__.py
@@ -132,9 +132,8 @@ class Dynamips(IModule):
 
         if not sys.platform.startswith("win32"):
             self._callback.stop()
-        if self._hypervisor_manager:
-            self._hypervisor_manager.stop_all_hypervisors()
 
+        self.reset()
         IModule.stop(self, signum)  # this will stop the I/O loop
 
     def _check_hypervisors(self):
@@ -175,11 +174,11 @@ class Dynamips(IModule):
         return instance_dict[device_id]
 
     @IModule.route("dynamips.reset")
-    def reset(self, request):
+    def reset(self, request=None):
         """
-        Resets the module.
+        Resets the module (JSON-RPC notification).
 
-        :param request: JSON request
+        :param request: JSON request (not used)
         """
 
         # stop all Dynamips hypervisors
diff --git a/gns3server/modules/iou/__init__.py b/gns3server/modules/iou/__init__.py
index bf13e665..47b0912f 100644
--- a/gns3server/modules/iou/__init__.py
+++ b/gns3server/modules/iou/__init__.py
@@ -112,11 +112,7 @@ class IOU(IModule):
         """
 
         self._iou_callback.stop()
-        # delete all IOU instances
-        for iou_id in self._iou_instances:
-            iou_instance = self._iou_instances[iou_id]
-            iou_instance.delete()
-
+        self.reset()
         IModule.stop(self, signum)  # this will stop the I/O loop
 
     def _check_iou_is_alive(self):
@@ -161,11 +157,11 @@ class IOU(IModule):
         return self._iou_instances[iou_id]
 
     @IModule.route("iou.reset")
-    def reset(self, request):
+    def reset(self, request=None):
         """
-        Resets the module.
+        Resets the module (JSON-RPC notification).
 
-        :param request: JSON request
+        :param request: JSON request (not used)
         """
 
         # delete all IOU instances
diff --git a/gns3server/server.py b/gns3server/server.py
index 5452ac23..c7237c91 100644
--- a/gns3server/server.py
+++ b/gns3server/server.py
@@ -215,6 +215,17 @@ class Server(object):
             log.info("ZeroMQ server listening to 127.0.0.1:{}".format(self._zmq_port))
         return self._router
 
+    def stop_module(self, module):
+        """
+        Stop a given module.
+
+        :param module: module name
+        """
+
+        if not self._router.closed:
+            self._router.send_string(module, zmq.SNDMORE)
+            self._router.send_string("stop")
+
     def _shutdown(self):
         """
         Shutdowns the I/O loop and the ZeroMQ stream & socket.
@@ -243,13 +254,18 @@ class Server(object):
         # terminate all modules
         for module in self._modules:
             if module.is_alive():
-                log.info("terminating {}".format(module.name))
-                module.terminate()
-                module.join(timeout=1)
+                log.info("stopping {}".format(module.name))
+                self.stop_module(module.name)
+                module.join(timeout=3)
+                if module.is_alive():
+                    # just kill the module if it is still alive.
+                    log.info("terminating {}".format(module.name))
+                    module.terminate()
+                    module.join(timeout=1)
 
         if stop:
             ioloop = tornado.ioloop.IOLoop.instance()
             if signum:
                 ioloop.add_callback_from_signal(self._shutdown)
             else:
-                self._shutdown()
+                ioloop.add_callback(self._shutdown)