Yes. You can configure the Junk Email settings of Outlook using a Group Policy
http://technet.microsoft.com/en-us/library/cc179183.aspx
The options available will vary for each client and have it's own configuration. You will need to download the Administrative Template (ADM) for Office XP, 2003, and 2007 in order to configure each.
In previous versions of Exchange (5.5, 2000, 2003 without service pack), all email that cannot be delivered ends up in the Badmail directory. This folder grows infinitely until it runs out of disk space.
Exchange Server 2003 Service Pack 1 changes that. By default, it will handle all "badmail" in a virtual way and no data trash is accumulated.
If you want to keep your badmail, you'll have changed a couple of registry settings:
HKLM\System\CurrentControlSet\Services\SMTPSVC\Queuing
Value: MaxBadMailFolderSize this is the size in KB.
Value: BadMailSyncPeriod specifies how often to check
the Badmail folder (in minutes).
If set to 0, badmail disappears. -1 reverts to pre-SP1 settings. However, like circular logging, this doesn't "rotate" messages - just collects messages till the max folder size is reached and then stops collecting more bad mail.
On Pre-Exchange Server 2003 SP1, the badmail folder contains messages that cannot be delivered, and also cannot be returned back to the sender. Therefore, the folder typically contains spam, and the files within the folder can usually just be deleted. You should find your SMTP server on such servers looking into your virtual SMTP protocol's properties (there is a badmail folder setting).
However, Exchange doesn't provide a setting to periodically empty the contents of the folder. The danger is that this folder will go un-monitored, and will continue to fill up.
This link could also be interesting to you:
Exchange Server Badmail Deletion and Archiving
Automatic deletion or archiving of
files in the badmail directory of SMTP
virtual servers.
Best Answer
As far as I know, iisreset doesn't stop the Exchange Information Store - only the SMTP service.
You could try iisreset /noforce or you could fire up IIS Manager on the server and from the menu choose Restart Internet Services on [server name] (which for all I know, could just be doing iisreset /noforce in the background).
I have to bounce IIS on our Exchange server periodically (3rd party app keeps crashing) and personally, I use the GUI as I seem to have more luck with it.