Know How to Decommission On-Premises Exchange Server Without Any Hassle

Aldrich Calvin | Modified: September 22, 2021 | General | 4 Minutes Reading

Thinking about how to decommission Exchange 2010 after Office 365 hybrid migration. Are you facing difficulty while performing this operation manually? Do not panic! This guide describes the best and most reliable approaches to decommission On-premises Exchange server into Office 365. So, let’s get started!

When the Exchange users wish to use the service of Office 365, then they first go for the Office 365 Deployment. As its name suggests ‘hybrid’, is the combination of cloud and On-premises. It provides the facility to use the Exchange Server with Exchange Online mailboxes. However, when the user or an organization wants to completely move their mailboxes from On-premises to Exchange Online. In such an instance, hybrid deployment creates the problem such as getting error messages. As a result, users are unable to decommission Exchange after Migration to Office 365. In the upcoming section, users will know the reason why hybrid deployment is not a good option for the Exchange mailbox migration.

Keep Away to Remove Exchange Server After Hybrid Migration: Know the Reason

From the last few years, the growing popularity of MS O365 and its advanced feature attracts the most users. Also, Office 365 Hybrid Server gives the flexibility of gradual migration to Online but it is up to some extent. Because when it comes to full migration from On-premises to Office 365, hybrid deployment becomes cumbersome.

The reason behind this is the requirement of a minimum of one On-premises hybrid server for user management. It is because of the presence of Active Directory Synchronization or DirSync. It is a part of the prerequisite that is mandatory to deploy a hybrid process. Its work is to make a copy of the local On-premises directory and then communicate into cloud tenant. So, when the DirSync (or Directory Synchronization) is enabled, most of the actions or task is managed from on-premises instead from O365. That is why organizations cannot remove on-premises mailboxes completely and move into Office 365 after hybrid migration.

Well! After understanding the reasons, let’s look at the approaches that help the users to remove Exchange 2013, 2010 from the hybrid configuration.

How to Decommission On-Premises Exchange Servers Hybrid Manually?

This workaround is helpful for those users who already move all the important On-premises mailboxes to Exchange Online. Now, they do not want to keep AD synchronization for user management on On-premises. So, follow this method to disable DirSync

Steps to Turn-off Directory Synchronization for Office 365

1. To start the process, you need to run the following command:

Get-OrganizationConfig | f1 PublicFoldersEnabled

Note: If the above-mentioned cmdlet is set up to Remote, then use batch migration process to move Public folder in MS Office 365 account.

2. Next, ensure that MX and Autodiscover DNS records are set for Office 365 Exchange Online rather than the local hybrid servers.

3. After that, you need to eliminate the SCP (Service Connection Point) values from the On-premises Exchange Server. This action ensures that you are using the DNS record for AutoDiscover. Use the following command to remove SCP.

Get-ClientAccessServer | Set-ClientAccessServer -AutoDiscoverServiceInternalUri $Null

4. In the MS Office 365 Admin portal, go to Admin Centers > > Exchange.

5. In EAC, click on mail flow option and then select connectors. Here, you can disable the inbound/outbound connectors that were used for the hybrid deployment process. Ensure that the connectors that are used currently are not deleted.

6. In order to delete the On-premises Exchange relationship, follow the below instructions

You have to login into Office 365 as an Administrator.
Next step is to select Exchange option.
Go to Organization option display at the left-side pane.
In the detailed pane, under Organization Sharing heading, remove the O365 to On-premises relationship by selecting the checkbox. Then, click on Bin icon to delete it.

7. After that, if you configured Exchange Hybrid with OAuth, then you have to disable it from Office 365 and local Exchange environment too. To do this, follow the below steps:

- Launch Exchange Management Shell and execute the below-mentioned command: Next, open PowerShell Window and connect it with Exchange Online to remove OAuth configuration

Get-IntraorganizationConnector -Identity ExchangeHybridOnPremisesToOnline | Set-IntraOrganizationConnector -Enabled $False

Next, open PowerShell Window and connect it with Exchange Online to remove OAuth configuration.
After that, type the following cmdlet and execute it

Run Get-IntraorganizationConnector -Identity ExchangeHybridOnlineToOnPremises | Set-IntraOrganizationConnector -Enabled $False

8. Finally, you can disable Directory Synchronization from the Exchange Online tenants. Now, On-premises Exchange Server is decommissioned

Looking for a reliable way to Migrate On-Premise Exchange to Exchange Online? Follow the respective article to get the most productive solution for the same.

Bringing It All Together

Due to the advanced functionality of Office 365, many enterprises moving towards it. However, users face problems while completely decommission On-premises Exchange Server after hybrid migration because of DirSync. Therefore, in this post, we have discussed the most appropriate method to remove Exchange Server after hybrid deployment.