diff --git a/openbsc/src/libmsc/smpp_vty.c b/openbsc/src/libmsc/smpp_vty.c
index c6bb74d..96447bf 100644
--- a/openbsc/src/libmsc/smpp_vty.c
+++ b/openbsc/src/libmsc/smpp_vty.c
@@ -119,7 +119,8 @@
 
 	vty_out(vty, "smpp%s", VTY_NEWLINE);
 	vty_out(vty, " local-tcp-port %u%s", smsc->listen_port, VTY_NEWLINE);
-	vty_out(vty, " system-id %s%s", smsc->system_id, VTY_NEWLINE);
+	if (smsc->system_id)
+		vty_out(vty, " system-id %s%s", smsc->system_id, VTY_NEWLINE);
 	vty_out(vty, " policy %s%s",
 		smsc->accept_all ? "accept-all" : "closed", VTY_NEWLINE);