diff --git a/examples/ipv6/native-border-router/slip-config.c b/examples/ipv6/native-border-router/slip-config.c
index daad4907a..84d256127 100644
--- a/examples/ipv6/native-border-router/slip-config.c
+++ b/examples/ipv6/native-border-router/slip-config.c
@@ -157,7 +157,7 @@ exit(1);
   argv += optind - 1;
 
   if(argc != 2 && argc != 3) {
-    err(1, "usage: %s [-B baudrate] [-H] [-L] [-s siodev] [-t tundev] [-T] [-v verbosity] [-d delay] ipaddress", prog);
+    err(1, "usage: %s [-B baudrate] [-H] [-L] [-s siodev] [-t tundev] [-T] [-v verbosity] [-d delay] [-a serveraddress] [-p serverport] ipaddress", prog);
   }
   slip_config_ipaddr = argv[1];