diff -uNr a/bitcoin/src/main.cpp b/bitcoin/src/main.cpp
--- a/bitcoin/src/main.cpp aeeffe8c603d726aae829c01f057ca0efdae8a84820a57e41d8282de988a74494f139842228bcc158fc8ec484f076c7b2187c4d6d14e7c998fa698570948992e
+++ b/bitcoin/src/main.cpp 0ccb0c29c0a3217d57f9bc72d87b497e64116a9f79e69277408750ee3dc95738ce52a70afece7a1054314100d84f93f6525ab514b8abd8ce78ab8ebd50e599a2
@@ -1901,6 +1901,11 @@
                         pfrom->PushMessage(inv.GetCommand(), (*mi).second);
                 }
             }
+            else
+            {
+                pfrom->Misbehaving(100);
+                return error("BANNED peer issuing unknown inv type.");
+            }
 
             // Track requests for our stuff
             Inventory(inv.hash);
@@ -2103,7 +2108,9 @@
 
     else
     {
-        // Ignore unknown commands for extensibility
+      // He who comes to us with a turd, by the turd shall perish.
+      pfrom->Misbehaving(100);
+      return error("BANNED peer issuing heathen command.");
     }