Everyone is familiar with the fact that priority of emails that are sent from Outlook or OWA can be changed very easily. Most of you will have used this feature at some point in your professional career, to get the attention of the recipient regarding the importance of the email that you are sending.
Though an email can be sent with “High Importance”, it makes no difference to Exchange 2010 by default. All emails will be queued and delivered in the order they are received. This is where “Priority Queuing” comes in and it will be useful to configure the feature, so that the emails that have high priority are processed and delivered before any other emails in the queue, regardless of when the emails were received by the server.
Priority queuing is disabled in Exchange 2010 by default. It is very easy to enable it – edit the EdgeTransport.exe.config file in the Bin directory and restart the Exchange Transport service. Let me explain the steps.
Navigate to the Bin directory and find EdgeTransport.Exe.Config file.
Open it using notepad and find the line that says PriorityQueuingEnabled is set to false.
Change the value from “false” to “true” and save the file.
Restart Exchange Transport service.
Once this is complete, Exchange 2010 will deliver high priority emails before any other ones and normal priority emails will be delivered before the low priority ones. By default, all emails sent from Outlook & OWA have normal priority.
You may want to change the maximum message size for high priority emails, as the default value is 250KB. The “MaxHighPriorityMessageSize” parameter controls the maximum allowed size for a high priority message.
If a high priority message is larger than the value of the “MaxHighPriorityMessageSize” parameter, the message is automatically downgraded from high priority to normal. To have the desired priority queuing, change the value of “MaxHighPriorityMessageSize” from 250KB to the one of your choice, say 5MB.