Vitezslav Kriz
--- a/doc/reference.rst
+++ b/doc/reference.rst
 Mandatory checks:
--- a/src/knot/zone/semantic-check.c
+++ b/src/knot/zone/semantic-check.c
+	}
+
+	// check glue record for delegation
+	for (int i = 0; i < ns_rrs->rr_count; ++i) {
+		const knot_dname_t *ns_dname = knot_ns_name(ns_rrs, i);
+		if (!knot_dname_is_sub(ns_dname, data->zone->apex->owner)) {
+			continue;
+		}
+
+		const zone_node_t *glue_node =
+			zone_contents_find_node(data->zone, ns_dname);
+
+		if (glue_node == NULL) {
+			/* Try wildcard ([1]* + suffix). */
+			knot_dname_t wildcard[KNOT_DNAME_MAXLEN];
+			memcpy(wildcard, "\x1""*", 2);