[rci]

Empezado por bmfranky

Hola, puedes pasar el codigo que usas para la consulta?
Yo uso esta
Que devuelbe un json con todos los datos incluyendo el desfase UTC, basado en la ip, mirad el ejemplo.

Lo saqué de internet: https://stackoverflow.com/questions/...server-using-c

Es posible que se pueda mejorar pero de momento uso este:

       private static DateTime GetNetworkTime()
       {
           //default Windows time server
           const string ntpServer = "time.windows.com";

           // NTP message size - 16 bytes of the digest (RFC 2030)
           var ntpData = new byte[48];

           //Setting the Leap Indicator, Version Number and Mode values
           ntpData[0] = 0x1B; //LI = 0 (no warning), VN = 3 (IPv4 only), Mode = 3 (Client Mode)

           var addresses = Dns.GetHostEntry(ntpServer).AddressList;

           //The UDP port number assigned to NTP is 123
           var ipEndPoint = new IPEndPoint(addresses[0], 123);
           //NTP uses UDP

           using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
           {
               socket.Connect(ipEndPoint);

               //Stops code hang if NTP is blocked
               socket.ReceiveTimeout = 3000;

               socket.Send(ntpData);
               socket.Receive(ntpData);
               socket.Close();
           }

           //Offset to get to the "Transmit Timestamp" field (time at which the reply 
           //departed the server for the client, in 64-bit timestamp format."
           const byte serverReplyTime = 40;

           //Get the seconds part
           ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);

           //Get the seconds fraction
           ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);

           //Convert From big-endian to little-endian
           intPart = SwapEndianness(intPart);
           fractPart = SwapEndianness(fractPart);

           var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

           //**UTC** time
           var networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);

           return networkDateTime.ToLocalTime();
       }

       // stackoverflow.com/a/3294698/162671
       private static uint SwapEndianness(ulong x)
       {
           return (uint)(((x & 0x000000ff) << 24) +
                          ((x & 0x0000ff00) << 8) +
                          ((x & 0x00ff0000) >> 8) +
                          ((x & 0xff000000) >> 24));
       }