diff --git a/ospf6d/ospf6_interface.c b/ospf6d/ospf6_interface.c
index c9c9011..26f68ac 100644
--- a/ospf6d/ospf6_interface.c
+++ b/ospf6d/ospf6_interface.c
@@ -59,7 +59,7 @@
 };
 
 struct ospf6_interface *
-ospf6_interface_lookup_by_ifindex (int ifindex)
+ospf6_interface_lookup_by_ifindex (ifindex_t ifindex)
 {
   struct ospf6_interface *oi;
   struct interface *ifp;