Topic Last Modified: 2007-01-24

You can determine the maximum number of recipients for a single message sent in one connection. The default is 100, which is the minimum number that is specified in Request for Comments (RFC) 821. Many clients return messages with a non-delivery report (NDR) after an error message is received. This indicates that the maximum number of recipients has been exceeded. The Simple Mail Transfer Protocol (SMTP) service does not return messages in this instance. It opens a new connection immediately and processes the remaining recipients. For example, if the recipient limit is set to 100 and a message with 105 recipients is received, the first 100 recipients are delivered in one connection. Then a new connection is opened, and the message is processed for the remaining five recipients.


To set recipient limits

  1. In Microsoft Management Console, select the SMTP virtual server, and then click Properties on the Action menu.

  2. On the Messages tab, in Limit number of recipients per message to, type a number to represent the recipient limit. To impose no limit, click to clear the check box.