RB:
As AG stated, take a look at http://support.microsoft.com/kb/308303 for information on how to limit the size of NDRs generated by SMTP. Be aware that this setting does not affect NDRs generated by the information store, so NDRs generated on Exchange 2003 SP1 or Exchange 2000 with the latest rollup for cached mode clients will still contain the original message and all its attachments. There is no way to change this behavior.
Setesh:
This blog entry is about Outlook clients that use MAPI to send messages to the Exchange server that exceed configured size limits. It sounds like the functionality you are referring to is the ability to block large messages coming in via SMTP. Prior to the updates that I described in this blog entry there was no way to keep Outlook in MAPI mode from sending messages that exceed size limits to the server. I apologize for any confusion and I hope this clears things up a bit.
Christian:
That's a good question.
The first thing to note is that this issue has technically existed in the product ever since Exchange 4.0.
The second thing to keep in mind is that hard drives have increased in size quite rapidly in the last decade. For consumer class hard drives, the top capacity was about 2 GB by the end of 1995, 10 GB by the end of 1997, and 20 GB by the end of 1999. These relatively small hard drive sizes meant that not a lot of people had huge files on their hard drives, and if they did they usually weren't the type of files that were likely to be sent as e-mail attachments.
So, to answer your question, even at the time of Exchange 2000's development this behavior actually was much more "exotic" than it is today in the world of 100 MB PPT files, multi-GB MP3 collections, and 500 GB hard drives.