Delaying the SMTP greeting
An SMTP greeting message can be delayed for a specified time interval, so that a connection from a client will be dropped if the client tries to send data during this time interval. This option can help prevent mail from spam-sending applications that send a high volume of messages very quickly. The connection is dropped as soon as a message is sent to the SMTP server before it is ready. This feature is not enabled by default, but can be enabled from the section SMTP Greeting Delay Options on the page
.Configure the SMTP greeting delay