DnsMessage query = new DnsMessage(record);
DnsMessage answer = _dnsClient.resolve(query);
incrementIteration();
ResponseCode responseCode = answer.getHeaderSection().getResponseCode();
if (responseCode == ResponseCode.NAME_ERROR)
{
_dnsClient.getCache().addNegativeRecord(query, answer);
throw new UnknownHostException(_record.getName().toString());
}