diff --git a/msg.go b/msg.go
index 5d7dbe0e..617c844e 100644
--- a/msg.go
+++ b/msg.go
@@ -126,6 +126,7 @@ var Class_str = map[uint16]string{
 	ClassCSNET:  "CS",
 	ClassCHAOS:  "CH",
 	ClassHESIOD: "HS",
+        ClassNONE:   "NONE",
 	ClassANY:    "ANY",
 }