diff --git a/src/lib/io/network.c b/src/lib/io/network.c
index fdf88bb02c32..a7449a918db6 100644
--- a/src/lib/io/network.c
+++ b/src/lib/io/network.c
@@ -1316,11 +1316,8 @@ static int fr_network_listen_add_self(fr_network_t *nr, fr_listen_t *listen)
 	/*
 	 *	Non-socket listeners just get told about the event
 	 *	list, and nothing else.
-	 *	In very specific cases a listener app_io may only
-	 *	have a close, so look for both open and close to
-	 *	determine what this is.
 	 */
-	if (listen->non_socket_listener || (!listen->app_io->open && !listen->app_io->close)) {
+	if (listen->non_socket_listener) {
 		fr_assert(listen->app_io->event_list_set != NULL);
 		fr_assert(!listen->app_io->read);
 		fr_assert(!listen->app_io->write);
diff --git a/src/listen/ldap_sync/proto_ldap_sync.c b/src/listen/ldap_sync/proto_ldap_sync.c
index 4ef2f195f4ae..63bd6a547a40 100644
--- a/src/listen/ldap_sync/proto_ldap_sync.c
+++ b/src/listen/ldap_sync/proto_ldap_sync.c
@@ -254,6 +254,7 @@ static int mod_open(void *instance, fr_schedule_t *sc, UNUSED CONF_SECTION *conf
 	li->app = &proto_ldap_sync;
 	li->app_instance = instance;
 	li->server_cs = inst->server_cs;
+	li->non_socket_listener = true;
 
 	/*
 	 *	Set configurable parameters for message ring buffer.