diff --git a/zebra/connected.h b/zebra/connected.h
index 289b03c..28387e9 100644
--- a/zebra/connected.h
+++ b/zebra/connected.h
@@ -41,7 +41,8 @@
 #ifdef HAVE_IPV6
 extern void
 connected_add_ipv6 (struct interface *ifp, struct in6_addr *address,
-		    u_char prefixlen, struct in6_addr *broad, char *label);
+		    u_char prefixlen, struct in6_addr *broad,
+		    const char *label);
 extern void
 connected_delete_ipv6 (struct interface *ifp, struct in6_addr *address,
 		       u_char prefixlen, struct in6_addr *broad);