MARKUS

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Net.NetworkInformation;

using System.Text;

using System.Threading.Tasks;

namespace CommonLib

{

    public class DNSHelper

    {

        public static IPAddress GetDnsAdress()

        {

            NetworkInterface[] networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

            foreach (NetworkInterface networkInterface in networkInterfaces)

            {

                if ((networkInterface.NetworkInterfaceType == NetworkInterfaceType.Ethernet ||

                    networkInterface.NetworkInterfaceType == NetworkInterfaceType.Wireless80211)

                    && networkInterface.OperationalStatus == OperationalStatus.Up)

                {

                    IPInterfaceProperties ipProperties = networkInterface.GetIPProperties();

                    IPAddressCollection dnsAddresses = ipProperties.DnsAddresses;

                    foreach (IPAddress dnsAdress in dnsAddresses)

                    {

                        if (dnsAdress.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)

                            return dnsAdress;

                    }

                }

            }

            return null;

        }

        public static async Task<IPHostEntry> GetHostEntryAsync()

        {

            IPHostEntry result = null;

            await Task.Factory.StartNew(() =>

            {

                try

                {

                    var ipaddress = CommonLib.DNSHelper.GetDnsAdress();

                    result = Dns.GetHostEntry(ipaddress);

                }

                catch (System.Net.Sockets.SocketException ex)

                {

                    if (ex.SocketErrorCode == System.Net.Sockets.SocketError.HostNotFound)

                    {

                        System.Diagnostics.Debug.WriteLine("DNS SocketError");

                        result = null;

                    }

                }

                catch (Exception ex)

                {

                    throw ex;

                }

            });

            System.Diagnostics.Debug.WriteLine("DNS END");

            return result;

        }

        public static IPHostEntry GetHostEntryTask()

        {

            IPHostEntry result = null;

            try

            {

                var ipaddress = CommonLib.DNSHelper.GetDnsAdress();

                var task = Task.Factory.StartNew(() =>

                {

                    result = Dns.GetHostEntry(ipaddress);

                });

                task.Wait();

            }

            catch (Exception ex)

            {

                if (ex.InnerException is System.Net.Sockets.SocketException)

                {

                    System.Diagnostics.Debug.WriteLine((ex.InnerException as System.Net.Sockets.SocketException).SocketErrorCode);

                }

                else

                {

                    System.Diagnostics.Debug.WriteLine(ex.ToString());

                }

            }

            return result;

        }

    }

}