diff --git a/model/ccnx-l3-protocol.cc b/model/ccnx-l3-protocol.cc
index da7ad29..f87a990 100644
--- a/model/ccnx-l3-protocol.cc
+++ b/model/ccnx-l3-protocol.cc
@@ -76,7 +76,7 @@
                    MakePointerChecker<CcnxForwardingStrategy> ())
     
     .AddAttribute ("EnableNACKs", "Enabling support of NACKs",
-                   BooleanValue (true),
+                   BooleanValue (false),
                    MakeBooleanAccessor (&CcnxL3Protocol::m_nacksEnabled),
                    MakeBooleanChecker ())
     .AddAttribute ("CacheUnsolicitedData", "Cache overheard data that have not been requested",