Are large messages slowing your Exchange server down?

re: Are large messages slowing your Exchange server down?

RB — Thu, 10 Nov 2005 11:24:16 GMT

Great work but...

1) It requires Outlook 2003 + SP2.
2) Exchange still attaches the original message + original attachments to the NDR

Is there a way to prevent Exchange to send NDR's above a certain size?
Or how do you prevent Exchange adding the original attachment to the NDR?

re: Are large messages slowing your Exchange server down?

AG — Thu, 10 Nov 2005 15:08:25 GMT

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SMTPSVC\Queuing\MaxDSNSize allows you to specify a maximum msg size to NDR the whole message.

Take a look at http://support.microsoft.com/?id=308303

re: Are large messages slowing your Exchange server down?

Setesh — Thu, 10 Nov 2005 16:29:11 GMT

"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 !

re: Are large messages slowing your Exchange server down?

Christian Schindler — Thu, 10 Nov 2005 19:18:04 GMT

also think that this is great work. But:

Why wasn't this considered upon development of the first release of Exchange 2000? This behavior is nothing "exotic"...when I think about efficient data transmission, this is "standard".

re: Are large messages slowing your Exchange server down?

Mike — Thu, 10 Nov 2005 22:13:25 GMT

Great work. Excellent blog entry...

re: Are large messages slowing your Exchange server down?

DaveMills — Thu, 10 Nov 2005 22:20:24 GMT

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.

re: Are large messages slowing your Exchange server down?

Christian Schindler — Fri, 11 Nov 2005 01:10:32 GMT

Dave,

thanks for sharing your thoughts... It's great to get feedback!

re: Are large messages slowing your Exchange server down?

RB — Fri, 11 Nov 2005 10:52:32 GMT

Dave & AG: thank you for your replies.

The article sounds promising, I can save resources on the SMTP side when sending NDRs to external recipients.

re: Are large messages slowing your Exchange server down?

Setesh — Tue, 15 Nov 2005 14:17:35 GMT

"Setesh:
This blog entry is about Outlook clients that use MAPI to send messages to the Exchange server that exceed configured size limits."

As stated, we currently use Outlook XP (MAPI) to send messages via Exchange 2003 SP1. If a user attempts to send a mail that is over the size limit they instantly get a popup message that states "The message being sent exceeds the message size established for this user."

re: Are large messages slowing your Exchange server down?

A_N_IV — Thu, 17 Nov 2005 23:27:06 GMT

I appreciate the new functionality, but would like to ask a question: Is there a product available that can integrate with Exchange and intercept large attachments, transfering those files in another fashion, say via HTTPS, and spawning an e-mail to the recipient with a link that allows them to download the file?

I am currently looking at products like HyperSend and Tumbleweed secure file transfer, but they do not integrate into Exchange, which poses the problem of getting the user base to adopt the technology, and then to actually use it.

If not, that may be a function MS may want to start trying to develop as an add-on product for exchange, as we all know, attachments just keep getting bigger and bigger...

re: Are large messages slowing your Exchange server down?

DaveMills — Sat, 19 Nov 2005 05:07:23 GMT

Setesh:
The error popup that you are seeing only happens in online mode after all the data has been uploaded to the server. You can observe this for yourself by composing a new message, attaching a large file to it, and then watching for transaction logs being generated on the server prior to the message being sent. In addition, the fix described in this blog entry is specific to cached mode, offline mode, and Outlook configured with a PST as its delivery location, so even with Outlook 2003 in online mode you will still experience the same behavior.

A_N_IV:
I believe that Outlook 2003 does have some level of integration with SharePoint to do something like what you are asking for. As for third party solutions, you might be able to find what you're looking for on our partner's page for archiving and compliance at http://www.microsoft.com/exchange/partners/archivingandcompliance.asp.