Exchange 2007 is a much different beast than older editions of the product and may reintroduce some limits that you thought you'd eradicated—or at least modified—in your environment. One such variable, the maximum size of a message destined for one of your mailboxes, may be one that you wish to reapply to your organization.
The maximum allowed message size in Exchange 2007 is managed by the various SMTP receive connectors that are installed in your Exchange organization. Exchange 2007 includes two default SMTP receive connectors—the Client SMTP Receive Connector and the Default SMTP Receive Connector. Bear in mind that, if you have Exchange 2007 running side-by-side with Exchange 2000 or 2003, you may need to manage the settings for the SMTP receive connector that accepts mail from those servers for delivery to Exchange 2007-based mailboxes. Otherwise, you need to change the settings for the Default Receive Connector (assuming you have added the ability to accept anonymous mail to the connector), or for the special receive connector you may have created in order to accept mail from the Internet.
In any case, the setting MaxMessageSize, which has a default of 10 MB in Exchange 2007, is the parameter that needs adjustment. If you want to get a look at the values for the MaxMessageSize parameter for all of the SMTP receive connectors in your Exchange organization, start up the command line-based Exchange Management Shell and issue the following command:
get-receiveconnector | select identity,maxmessagesize
The output in Figure A shows you that, for the three Exchange servers in this organization, all of the installed SMTP receive connectors have a maximum message size of 10 MB.
|The six SMTP receive connectors have a maximum message size of 10MB.|
Now, to increase this to something larger—say 30 MB—use the set-receiveconnector, as in the following command:
set-receiveconnector "Connector Name" -maxmessagesize 30MB
As I mentioned before, make sure to run this against the right receive connector.