private IPAddress[] GetDnsRecords(string hostName, IPAddress dnsServer)
{
IntPtr ptr = default(IntPtr);
List <IPAddress> list = new List <IPAddress>();
IntPtr zero = IntPtr.Zero;
IPv4Array iPv4ArrayFromIPAddress = GetIPv4ArrayFromIPAddress(dnsServer);
if (DnsQueryA(hostName, 1, 72, ref iPv4ArrayFromIPAddress, ref ptr, ref zero) == 0)
{
DnsRecordA dnsRecordA = (DnsRecordA)Marshal.PtrToStructure(ptr, typeof(DnsRecordA));
IPAddress addressFromRecord = GetAddressFromRecord(dnsRecordA);
if (addressFromRecord != IPAddress.None)
{
list.Add(addressFromRecord);
}
while (!(dnsRecordA.NextRecord == IntPtr.Zero))
{
dnsRecordA = (DnsRecordA)Marshal.PtrToStructure(dnsRecordA.NextRecord, typeof(DnsRecordA));
addressFromRecord = GetAddressFromRecord(dnsRecordA);
if (addressFromRecord != IPAddress.None)
{
list.Add(addressFromRecord);
}
}
}
return(list.ToArray());
}
private IPAddress GetAddressFromRecord(DnsRecordA record)
{
if (record.Type != 1)
{
return(IPAddress.None);
}
if ((record.Flags & 3) >= 2)
{
return(IPAddress.None);
}
return(new IPAddress(record.Data));
}