One can send email from their domain via JMail script. Below mentioned is sample script for JMail:
Set JMail = Server.CreateObject("JMail.SMTPMail")
JMail.ServerAddress = "mail.<your domain here>"
JMail.Sender = "sender's email address"
JMail.Subject = "Here subject line of the email"
JMail.AddRecipient "Recipient Email address"
JMail.Body = "Body Contents of the message"
JMail.Priority = 1 ' Set Priority [1- Urgent, 3-Normal, 5-Lowest]