VB.net Sending Email using Exchange Server

System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient("mydomainserver");
           client.Credentials = new System.Net.NetworkCredential("userid", "password", "domain");
           System.Net.Mail.MailMessage mail = new System.Net.Mail.MailMessage();
           mail.From = new System.Net.Mail.MailAddress("abc@mydomain.com");
           mail.To.Add("abcd@xyz.com");
           mail.Subject = "Yoursubject";
           mail.IsBodyHtml = true;
           mail.Body = "test Emailbody";
           client.Send(mail);