diff --git a/zebra/interface.c b/zebra/interface.c
index ce31277..3919c3f 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -407,9 +407,9 @@
 	  ifc = listgetdata (node);
 	  p = ifc->address;
 	  
-	  if (p->family == AF_INET)
+	  if (p->family == AF_INET
+	      && (rn = route_node_lookup (zebra_if->ipv4_subnets, p)))
 	    {
-	      rn = route_node_lookup (zebra_if->ipv4_subnets, p);
 	      route_unlock_node (rn);
 	      addr_list = (struct list *) rn->info;