Currently we have NDRs disabled. This hasn't caused much of a problem, except when external people try to send us large messages, as our message size limit is 10MB. Since NDRs are disabled, nobody recieves notification that the message is exceeding message size limits. I've been told I can use Transport rules to reject messages over a certain size. However it seems that when I try this the message size limits take precedence as the message is rejected (silently, since NDRs are off) before the transport rules can even analyze the message. Are these assumptions accurate? If so, is the only way to reject larger messages to set my global message size limit higher than the actual limit I want (lets say 100MB), and then set the transport rule to the actual message limit size I want (like 10MB)?

We can set message size limits in 5 places: 1. Global 2. Send connectors 3. Recieve Connectors 4. User level 5. Transport rules http://www.exchange-genie.com/2007/11/how-to-set-message-size-limits-in-exchange-2007/ you also need to make sure you have raise the message limt @ proper configuration http://exchangepedia.com/blog/2007/09/exchange-server-2007-setting-message-size.htmlVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Hi Brett, If you would just like to notify external senders when sending large messages, I would like to explain that you could set Message limit on the Receive Connector which used to receive message from external senders. When external sender sends a large message which exceed the message size limit on the Receive Connector, the Exchange server will reject message by return a 552 5.3.4 error in the SMTP session before receiving the message. The remote server should be response to generate the NDR message. ~~~~~~~~~~~~~~~~ Mike Shen TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com ~~~~~~~~~~~~~~~~