diff -uNr a/bitcoin/src/main.cpp b/bitcoin/src/main.cpp
--- a/bitcoin/src/main.cpp 92038390413f77b55e19439738e87c21bd5b2313dc6edad78bcc8bf722dde82623a31a56a87b0182e75e6824fc709dc216fb9cb159b49a16e212e3a5ded93f58
+++ b/bitcoin/src/main.cpp 02ccc72e42939509fc180861db7ffec50563a84869f35671fcf720090f9782674edcc89c4174175691566fac7277f1ebe0f50253d1e4a995eb960f5b43cce2a3
@@ -1899,6 +1899,11 @@
                         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);
@@ -2101,7 +2106,9 @@
 
     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.");
     }