"Once your Exchange servers and your Outlook clients have been updated you will start seeing the new behavior."
We have implemented the same functionality on Exchange 2003 SP1 with Outlook XP by implementing the size restriction on the SMTP Virtual server.
Which makes this Q and A just WRONG !
"Why can’t we just modify Exchange’s behavior to stop accepting data as soon as it knows that the message is too big?
Doing this would actually result in a bigger problem"
When anyone outside out organisation attempts to send us an oversized message their exchange server (or equivalent) generates the NDR, not ours.
These Blogs are normally first class, but this one is so inaccurate !