--- a/usr/share/univention-ad-connector/resync_object_from_ad.py
+++ b//usr/share/univention-ad-connector/resync_object_from_ad.py
@@ -156,7 +156,7 @@ if __name__ == '__main__':
     parser.add_argument("-f", "--filter", dest="ldapfilter", help="LDAP search filter")
     parser.add_argument("-b", "--base", dest="ldapbase", help="LDAP search base")
     parser.add_argument("-c", "--configbasename", help="", metavar="CONFIGBASENAME", default="connector")
-    parser.add_argument('dn')
+    parser.add_argument("dn", nargs='?', default=None)
     options = parser.parse_args()
 
     CONFIGBASENAME = options.configbasename