Exchange 2010 : Create a Message Send Size Limit For A Subset Of Users Within an Exchange Organisation

Exchange 2010 : Create a Message Send Size Limit For A Subset Of Users Within an Exchange Organisation

We recently encountered a requirement to limit a subset of users to a maximum send size without imposing this organisation wide – this was achieved this using a transport rule, the steps are outlined below.

1. Create a Distribution Group that contains all your Exchange Users that you wish to limit email size for. For this example this group has an email address of [email protected].
2. Create a new Dsn Error message: New-SystemMessage -DsnCode 5.7.50 -Language En -Internal $True -Text ‘Your message has not been sent as it exceeds the maximum allowed message size of 20MB. Please contact the helpdesk for support on 123 or click here to raise a support ticket <a href=”http://helpdesk/riaseticket.html”>Open Support Ticket</a>.’
3. Next create a new transport rule (change the [email protected] email address to reflect the group created in step 1) : New-TransportRule “Block Internal Email over 50MB” -FromMemberOf “[email protected]” -attachmentSizeOver 50MB -RejectMessageEnhancedStatusCode “5.7.50” -RejectMessageReasonText “Your message has not been sent as it exceeds the maximum allowed message size.” -SentToScope “InOrganisation”
4. Verify the priority of any other transport rules configured in your Exchange Organisation.