I am currently the IT Director of an environment where we are using Blackberrys with the Blackberry Internet Service. We host an Exchange 2003 environment on a Windows 2003 Server. My question is: Can we somehow prevent NDR's from being sent to the originating email address from the Blackberry account when they have sent too large of a file? For example, our current limit on the Blackberry account is 5 MB and when a message is forwarded to the BIS from Exchange an NDR is generated back to the originator from the BIS Host. Can Exchang be set up to not forward any message over a certain size and then to also not generate an NDR just for those messages?