protected void Button1_Click(object sender, EventArgs e)
        {
            string Status = "Успешно!";

            StringBuilder sb = new StringBuilder();
            sb.Append("Title=");
            sb.Append("Description=");
            sb.Append("Keywords=");
            sb.Append("productName=");

            string UrlData = "http://localhost/TestMVC/Service/PostData";

            System.Net.WebRequest request = System.Net.WebRequest.Create(UrlData);
            request.Method = "POST";
            byte[] byteArray = Encoding.Default.GetBytes(sb.ToString());//определяем что передаем в байтах 
            Stream newStream = request.GetRequestStream();
            newStream.Write(byteArray, 0, byteArray.Length);
            newStream.Close();
            request.Credentials = new System.Net.NetworkCredential("http", "111");

            try
            {
                System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
                using (StreamReader stream = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                {
                    Response.Write(stream.ReadToEnd());
                }
            }
            catch (WebException err)
            {
                Status = "Ошибка доступа к сервису:" + err.Message;
                Response.Write(Status);
            }

        }

 //[Authorize]
    public class ServiceController : Controller
    {
        [HttpPost]
        public string PostData()
        {
            int Len = (int)Request.InputStream.Length;
            byte[] value = new byte[Len];
            Request.InputStream.Read(value, 0, Len);

            var fileName = "D:/1.txt";//путь расположения файла
            var file = new FileStream(fileName, FileMode.Create);
            file.Write(value, 0, Len);
            file.Close();

            if (value != null)
            {
                return "Обработка вх. данных " + value.Length + " завершена!";
            }
            return "Ok! public string PostData  Request.InputStream.Length=" + Request.InputStream.Length;
        }

    }

 <authentication mode="Forms">
      <forms loginUrl="~/Account/Login" timeout="2880">
        <credentials passwordFormat="Clear">
          <user name="http" password="111" />
        </credentials>
      </forms>
    </authentication>