diff --git a/lcpng_if_sync.c b/lcpng_if_sync.c
index 9b33f3b..4d84570 100644
--- a/lcpng_if_sync.c
+++ b/lcpng_if_sync.c
@@ -524,7 +524,7 @@ lcp_itf_interface_add_del (vnet_main_t *vnm, u32 sw_if_index, u32 is_create)
       if (!sup_lip)
 	return NULL;
 
-      name = format (name, "%s.%d", sup_lip->lip_host_name, sw->sub.id);
+      name = format (name, "%s.%d%c", sup_lip->lip_host_name, sw->sub.id, 0);
 
       LCP_IF_INFO (
 	"interface_%s: %U has parent %U, auto-creating LCP with host-if %s",