Azure Hybrid & Cloud Migration Blog

Sometime back Exchange Server 2010 introduced a new feature called Shadow Redundancy Promotion. This feature enables Exchange Hub Transport Server maintains a local copy of the message before the next destination server acknowledge the receipt of the message. If the next hop server fails to provide the successful receipt acknowledgement then Exchange Hub Transport Server tries to re-send the communication again.

Let me try to elaborate it, Exchange  2010 SP1 and newer version uses Shadow Redundancy Promotion feature, which ensures that each message which submitted for transportation stays on two or more of Exchange Hub Transport Server in the AD site if next hope destination server is not reachable. By default shadow redundancy feature is disabled and it is upto Exchange administrator to enable it or not.

How to enable Shadow Redundancy Feature for your Exchange Hub Transport Servers?

For enabling Exchange Shadow Redundancy Feature for your Exchange 2010 Hub Transport servers, we have to change the EdgeTransport.exe.config file located within your Exchange server installation directory at “Program Files\Microsoft\Exchange Server\V14\bin”. Within EdgeTransport.exe.config file change the “ShadowRedundancyPromotionEnabled” settings to “TRUE” which is set to false by default.

Note: Make sure that you change the EdgeTransport.exe.config file for all your Exchange Hub Transport Servers available in the environment.

Cheers!