How to config smtp server

Hi,

I have create web application send mail. i use this code
con.Open();
  com = new SqlCommand("select mailid,password='" + TextBox2.Text + "' from registration where userid='" + TextBox1.Text + "'", con);
  dr = com.ExecuteReader();
  if (dr.Read())
  {
  mid = dr["mailid"].ToString();
  var fromAddress = new MailAddress("[email protected]", "Cloud Storage");
  var toAddress = new MailAddress(mid, "Cloud Storage");
  const string fromPassword = "pa$$word123";
  const string subject = "Verification Code";

  int n = _r.Next();
  body = n.ToString();
  Session["msg"] = body.ToString();
  var smtp = new SmtpClient
  {
  Host = "smtp.gmail.com",
  Port = 587,
  EnableSsl = true,
  DeliveryMethod = SmtpDeliveryMethod.Network,
  UseDefaultCredentials = false,
  Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
  };
  using (var message = new MailMessage(fromAddress, toAddress)
  {
  Subject = subject,
  Body = body
  })
  {
  smtp.Send(message);
  //smtp.Send(message);
  }
  Session["Username"] = TextBox1.Text.ToString();
  Response.Redirect ("Verification.aspx");
  }
  else
  {
 
  Response.Write("Invalid Login");
  }
 
but error at not remote server (sending failed) so how to set smtp server