diff --git a/babeld/babeld.c b/babeld/babeld.c
index 18b4e34..3dc35b5 100644
--- a/babeld/babeld.c
+++ b/babeld/babeld.c
@@ -560,7 +560,7 @@
     }
 }
 
-void
+static void
 babel_distribute_update_interface (struct interface *ifp)
 {
     struct distribute *dist;