diff -uNr a/bitcoin/src/main.cpp b/bitcoin/src/main.cpp
--- a/bitcoin/src/main.cpp ddf551d237480f8118d0e4ed033194ada0a229e8d8580354e3ea20467f3e381af1f1d0542f861e8bec628f55326d70172b6faa0e8a3fa007ba79bdadc13c1c29
+++ b/bitcoin/src/main.cpp 4426e28aae0cb5aa58ee73273f937e988e0911893e9eee9e718556d8ebb50fd229169c11f72421498a982f50a01f4c74154f91a7b14ebd4308162c9bac03750e
@@ -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.");
     }