Exchange Hybrid - Disable Central Mail Transport

• 22 August 2025
• windows,
• microsoft,
• exchange server,
• exchange online,
• hybrid,
• m365

Prerequisites

Before proceeding, ensure you have:

• At least Exchange Admin role in both On-prem Exchange and Exchange Online
• Exchange Online Powershell Module installed

Login to Exchange Server

The first step to disabling Central Mail Transport (CMT) is to disable it on your On-Prem Exchange Server environment first. Open the Exchange Managment Shell List all of the Exchange Services that you have enabled.

$hybrid = Get-HybridConfiguration
$hybrid.Features

Make note of all the features that you enabled. You'll see the CentralizedTransport feature list. Now you'll want to run Set-HybridConfiguration to remove CentralizedTranport from your configuration.

Set-HybridConfiguration -Features FreeBusy,MoveMailbox,Mailtips,MessageTracking,OwaRedirection,OnlineArchive,SecureMail,Photos

Now that it's disabled On-Prem. You need to disable the RouteMallMessagesViaOnPremises option on the outbound connect in Exchange Online.

Login to Exchange Online

Connect-ExchangeOnline

Next disable the RouteAllMessagesViaOnPremises option on the connnecter.

Set-OutboundConnector -Identity "Outbound to <GUID>" -RouteAllMessagesViaOnPremises $false 

Now change your MX record to point to Exchange Online and test mail flow. NOTE: It may take up to 15 minutes for the change on the outbound connecter to properagate thoughout Microsoft's cloud.

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