diff --git a/setup.py b/setup.py
index c7f6929..42a46c3 100644
--- a/setup.py
+++ b/setup.py
@@ -24,6 +24,7 @@ setup(name='vlanmang',
         'pysnmp',
         'pysnmp-mibs',
         'mock',
+        'pyasn1==0.4.8',
     ],
     extras_require = {
         'dev': [ 'coverage' ],