diff --git a/ospf6d/ospf6_neighbor.h b/ospf6d/ospf6_neighbor.h
index 441ab81..8f94790 100644
--- a/ospf6d/ospf6_neighbor.h
+++ b/ospf6d/ospf6_neighbor.h
@@ -105,7 +105,7 @@
 #define OSPF6_NEIGHBOR_LOADING  7
 #define OSPF6_NEIGHBOR_FULL     8
 
-extern char *ospf6_neighbor_state_str[];
+const extern char *ospf6_neighbor_state_str[];
 
 
 /* Function Prototypes */