We have a requirement to somehow throttle outbound SMTP mail.Our primary internet link is also out SMTP mail link. When one of our users sends a large email with many recipients and an attachment over 1MB our Internet link becomes unusuable as the outbound link is completely saturated.We use Exchange 2003, and we have looked at using routing rules or restricting outbound smtp connections but the latter appeared to adversely affect our users connecting the exchange internally.We use the messagelabs anti spam service and were contemplating using them to restrict the number of concurrent connections but this will delay all email.Routing rules appears to be limited to email attachment size but not the number of recipients, which is the key issue for us.Ideally we'd like to setup another outbound mail queue that routes emails with a large number of recipients and attachments over 1MB but this appear to be an option.Does anyone have any thoughts as to how this can be best achieved using exhange as the control point?Thanks alotRoger

I'm afraid that in 2003 you can influence mail routing only by using address space & costs, not the mail size or number of recipients.Perhaps its an option to have Exchange queue large emails using the connector's Delivery Options tab, check Use Different Delivery Times For Oversize Messages, set Oversize Messages Are Greater Than (KB) and set the Connection Time (of oversized messages) to run during non-peak hours. Also make sure CheckConnectorRestrictionsis set (see http://support.microsoft.com/kb/277872).Note that if you send large attachments to multiple recipients and you're using the DNS option on the send connector, you will send <mailsize> times <recipients>. You can reduce traffic by usinga smart host instead.