diff --git a/lib/isc/include/isc/eventclass.h b/lib/isc/include/isc/eventclass.h
index 1f773505c8..3bb50c878a 100644
--- a/lib/isc/include/isc/eventclass.h
+++ b/lib/isc/include/isc/eventclass.h
@@ -45,6 +45,7 @@ ISC_LANG_BEGINDECLS
 #define	ISC_EVENTCLASS_DNS		ISC_EVENTCLASS(4)
 #define	ISC_EVENTCLASS_APP		ISC_EVENTCLASS(5)
 #define	ISC_EVENTCLASS_OMAPI		ISC_EVENTCLASS(6)
+#define	ISC_EVENTCLASS_RATELIMITER	ISC_EVENTCLASS(7)
 
 /*
  * Event classes >= 1024 and <= 65535 are reserved for application use.