Index: modules/univention/s4connector/s4/dns.py
===================================================================
--- modules/univention/s4connector/s4/dns.py	(Revision 77820)
+++ modules/univention/s4connector/s4/dns.py	(Arbeitskopie)
@@ -1389,7 +1389,10 @@
 			zone = univention.admin.handlers.dns.reverse_zone.object(None, s4connector.lo, position=None, dn=searchResult[0][0], superordinate=None, attributes=[])
 		zone.open()
 		if set(ns) != set(zone['nameserver']):
-			if soa['mname'] not in ns:
+			mname = soa['mname']
+			if mname and mname[-1] != ".":
+				mname = "%s." % mname
+			if mname not in ns:
 				ns.insert(0, soa['mname'])
 			zone['nameserver'] = ns
 			modify = True