diff --git a/Shorewall/Actions/action.dropNotSyn b/Shorewall/Actions/action.dropNotSyn
index 8516623fd..a4508fef0 100644
--- a/Shorewall/Actions/action.dropNotSyn
+++ b/Shorewall/Actions/action.dropNotSyn
@@ -29,10 +29,10 @@ DEFAULTS -
 ?if passed(@1)
     ?if @1 eq 'audit'
         ?require AUDIT_TARGET
-	A_DROP {proto=6!syn}
+	A_DROP {proto=6:!syn}
     ?else
         ?error "Invalid argument (@1) to dropNotSyn"
     ?endif
 ?else
-    DROP {proto=6!syn}
+    DROP {proto=6:!syn}
 ?endif