We have already demonstrated How to Configure Message Size Limits in Exchange Server 2007 SP1. In this screencast, we will demonstrate how to configure the maximum message size limit in Outlook Web Access (OWA) by modifying the maxRequestLength parameter in web.config file.
If the maximum message size that can be sent from a mailbox exceeds the maxRequestLength, you may get the following errors in OWA:

– The attachment you are trying to upload exceeds the maximum size limit for attachments allowed by your organization. For more information, contact technical support for your organization.
– The files … were not attached because they exceed the maximum size limit of … (MB) for attachments.
– This message could not be sent because it exceeds the maximum size allowed.

In addition, if your Exchange 2007 server is running on a Windows Server 2008, you have to configure Outlook Web Access to allow content that is equal to the size of the maximum message size. Failing to do this will result in the following errors, when you use OWA to send a large attachment :

– Server Error 404 – File or directory not found. The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.
– Server Error in Application DEFAULT WEB SITE/OWA. HTTP Error 404.13 – Not Found. The request filtering module is configured to deny request that exceeds the request content length.

In our demo, we are configuring the maximum message size in OWA on an Exchange server 2007 running on Windows Server 2008.You can get the list of the commands used in the demo

from here
.

Step 1 In the first step, we configure the maxRequestLength parameter in web.config file to match the Maximum Message Size in Exchange 2007.

Step 2 If you are running Exchange 2007 on a Windows Server 2008, you have to adjust maxRequestLength too. In this step, you can see how to set this parameter. Finally, we test the result by sending a large attachment using OWA.