程序很简单，发现有些email server不能通过

gmail,iis/argosoft email server通过
winwebmail,kerio email server，21cn.com 通不过，基本都抱未通过认证或Failure sending mail



MailMessage message = new MailMessage();
message.From = new MailAddress("aaaa@mydomain.com", "市场部");
message.Sender = new MailAddress("aaaa@mydomain.com", "市场部");
message.To.Add("aaaa@mydomain.com");
message.Subject = "Subject Of the Mail";
message.Body = "Body of the Mail";
message.IsBodyHtml = true;
message.SubjectEncoding = System.Text.Encoding.UTF8;
message.BodyEncoding = System.Text.Encoding.UTF8;
//message.Priority = MailPriority.High;

SmtpClient client = new SmtpClient("219.131.xxx.xxx");
//SmtpClient client = new SmtpClient("192.168.1.168");
//client.EnableSsl = true;

client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user", "password");

client.DeliveryMethod = SmtpDeliveryMethod.Network;

//client.
client.Send(message);