diff --git a/ietf/utils/test_smtpserver.py b/ietf/utils/test_smtpserver.py
index 1475c9637..73535d010 100644
--- a/ietf/utils/test_smtpserver.py
+++ b/ietf/utils/test_smtpserver.py
@@ -14,7 +14,8 @@ class AsyncCoreLoopThread(object):
         """Start the listening service"""
         self.exit_condition = []
         kwargs={'exit_condition':self.exit_condition,'timeout':1.0} 
-        self.thread = threading.Thread(target=self.wrap_loop,kwargs=kwargs )
+        self.thread = threading.Thread(target=self.wrap_loop, kwargs=kwargs)
+        self.thread.daemon = True
         self.thread.start()     
 
     def stop(self):