diff --git a/tests/smpp_test_runner.py b/tests/smpp_test_runner.py
old mode 100644
new mode 100755
index 7a3a342..f6567d9
--- a/tests/smpp_test_runner.py
+++ b/tests/smpp_test_runner.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 
 # (C) 2014 by Holger Hans Peter Freyther
 # based on vty_test_runner.py: