public static QueryResult DNSQuery(IPAddress dnsServer, string domain)
{
if (dnsServer == null)
dnsServer = IPAddress.Parse("8.8.8.8");
QueryResult queryResult = new QueryResult()
{
Domain = domain,
DNS = dnsServer.ToString(),
NSCount = -1
};
Response response = null;
try
{
// create a DNS request
Request request = new Request();
request.AddQuestion(new Question(domain, DnsType.NS, DnsClass.IN));
response = Resolver.Lookup(request, dnsServer);
}
catch (Exception ex)
{
queryResult.Error = ex.Message;
}
if (response == null)
{
queryResult.Info = "No answer";
return queryResult;
}
queryResult.Info = response.AuthoritativeAnswer ? "authoritative answer" : "Non-authoritative answer";
// queryResult.NSCount = response.Answers.Length + response.AdditionalRecords.Length + response.NameServers.Length;
foreach (Answer answer in response.Answers)
{
if (answer.Record != null)
queryResult.NSList.Add(answer.Record.ToString());
}
foreach (AdditionalRecord additionalRecord in response.AdditionalRecords)
{
if (additionalRecord.Record != null)
queryResult.NSList.Add(additionalRecord.Record.ToString());
}
foreach (NameServer nameServer in response.NameServers)
{
if (nameServer.Record != null)
queryResult.NSList.Add(nameServer.Record.ToString());
}
queryResult.NSCount = queryResult.NSList.Count;
return queryResult;
}