management/dns_update.py.get_secondary_dns: changed to additionally query IPv6 address

management/dns_update.py

@@ -875,7 +875,12 @@ def get_secondary_dns(custom_dns, mode=None):
 			# resolve to an IP address. Otherwise just return the hostname.
 			if not hostname.startswith("xfr:"):
 				if mode == "xfr":
+					ipv6_response = dns.resolver.query(hostname+'.', "AAAA")
+					if len(ipv6_response) != 0:
+						values.append(str(ipv6_response[0]))
 					response = dns.resolver.query(hostname+'.', "A")
+					if len(response) == 0:
+						continue
 					hostname = str(response[0])
 				values.append(hostname)