sending mail

SqlCommand cmd2 = new SqlCommand("select name,femail from gr where inum='" + mylist[i].ToString() + "'", conn);
                         SqlDataReader rewder = cmd2.ExecuteReader();
                         while (rewder.Read())
                         {
                             MailAddress fromAddress = new MailAddress("yashpal@hry.nic.in", "Arun Trial for Email");

                             // You can specify the host name or ipaddress of your server
                             // Default in IIS will be lo
                             //smtpClient.Host = "localhost";
                             smtpClient.Host = "mail.nic.in";

                             //Default port will be 25
                             smtpClient.Port = 993;
                             smtpClient.EnableSsl = true;
                             //From address will be given as a MailAddress Object
                             message.From = fromAddress;
                             smtpClient.UseDefaultCredentials = true;
                            //  smtpClient.Credentials =  System.Net.NetworkCredential(userName, password);

                             // To address collection of MailAddress
                             message.To.Add(rewder[1].ToString());
                             message.Subject = "IAS's Transfer Orders";

                             // Send SMTP mail
                             
                             smtpClient.Send(message);