/// <summary>
/// Convenience method resolving and returning NS RRs.
/// </summary>
/// <param name="domain">
/// The domain name to resolve.
/// </param>
/// <returns>
/// An enumeration of NS Records. See <see cref="NSRecord"/>
/// </returns>
public IEnumerable <NSRecord> ResolveNS(string domain)
{
DnsResponse response = this.Resolve(DnsRequest.CreateNS(domain));
if (response == null || !response.HasNameServerRecords)
{
return(null);
}
return(response.AnswerRecords.NS);
}
/// <summary>
/// Resolves all the name server names for a given domain
/// </summary>
/// <param name="domain"></param>
/// <returns>An enumeration of name server names</returns>
public IEnumerable <string> GetNameServerNames(string domain)
{
DnsResponse response = this.Resolve(DnsRequest.CreateNS(domain));
if (response == null)
{
yield break;
}
IEnumerable <DnsResourceRecord> nsRecords = null;
if (response.HasAnswerRecords)
{
nsRecords = response.AnswerRecords;
}
else if (response.HasNameServerRecords)
{
nsRecords = response.NameServerRecords;
}
if (nsRecords == null)
{
yield break;
}
string serverName = null;
foreach (DnsResourceRecord record in nsRecords)
{
serverName = null;
switch (record.Type)
{
default:
break;
case DnsStandard.RecordType.NS:
serverName = ((NSRecord)record).NameServer;
break;
case DnsStandard.RecordType.SOA:
serverName = ((SOARecord)record).DomainName;
break;
}
if (serverName != null)
{
yield return(serverName);
}
}
}