Exchange Hybrid Test Plan Checklist

Exchange Server on-premises to Office 365 or Microsoft 365 migration requires intensive planning and preparation before you can start the migration. This is referred to as pre-migration checklist.

Similarly, you also need to have a post-migration test plan or checklist to verify if everything is working as it should. Sometimes, it may seem well, but you may encounter errors or issues as soon as you begin managing the Office 365 tenant, such as users can't view the shared calendar or connect to shared mailboxes.

To avoid such challenging situations after a complete migration, you should implement a post-migration test plan to thoroughly test all the functionalities in both environments before moving your users and mailboxes from on-premises Exchange Server to Office 365 tenant.

In this article, we have discussed an Exchange hybrid test plan checklist or post Exchange on-premises to Office 365 checklist to test all the functionalities and verify a healthy Exchange and Office 365 coexistence (hybrid setup).

Exchange Hybrid Post-Migration Checklist

Below is the Exchange hybrid test plan checklist, which includes important post Exchange on-premises to Office 365 migration steps, to identify if anything is broken before moving all the users and mailboxes from the on-premises Exchange Server to Office 365.

1. Test the Mail Flow

Get started by creating a user mailbox in Exchange hybrid configuration. You can create a new Microsoft mailbox for an existing user or create a new Microsoft 365 mailbox for a new user. It is recommended to create two Office 365 mailboxes - one for a new user and another for an existing user, to test both organizations' hybrid mail flow and GAL visibility.

You can use the Exchange Admin Center (EAC) or Exchange Management Shell to create Office 365 mailbox. To create the mailbox via EAC, go to recipients > mailboxes and click the + icon. Then choose Office 365 mailbox option.

Now add the Exchange Online license to the user and sync to Office 365 using Azure AD Connect. Similarly, you can create mailbox for the existing user and enable it by assigning the Exchange Online license and then synchronizing using Azure AD.

To test email flow, add the user account in Outlook and then draft a test email. Next, select an on-premises mailbox address from the GAL list and send the test email to the on-premises user's mailbox.

Now check the on-premises user's mailbox in Outlook. The mail flow from Office 365 mailbox to on-premises Exchange is working, if it receives the email.

Similarly, send a test email from on-premises Exchange to Office 365 user's mailbox and check the Office 365 Outlook Inbox for incoming email. Again, if the Office 365 user receives an email from the on-premises Exchange user, the mail flow from on-premises to Office 365 is working.

Finally, send a test email from on-premises and Office 365 user mailbox to external email servers, such as Gmail or Hotmail and vice versa, to ensure mail flow is working fine.

2. Check GAL

To check GAL, draft an email in Outlook client from both on-premises and Office 365 user mailboxes and then click on the 'Address Book'.

Next, choose 'All users' and check if users from both on-premises Exchange and Office 365 are visible in the GAL list of the on-premises and Office 365 user mailboxes.

This will help you verify Office 365 and on-premises Global Address List (GAL) visibility.

3. Check Shared Mailbox Access

In this test, you need to create Office 365 Shared Mailbox in Exchange hybrid configuration and check if both on-premises and Office 365 users can access the Shared Mailbox. This will also help you verify hybrid mail flow between both organizations.

Do not create a shared mailbox using on-premises or Office 365 Exchange Admin Center. Instead, always use Exchange Management Shell in Exchange hybrid to create Office 365 shared mailboxes using the New-RemoteMailbox and Enable-RemoteMailbox PowerShell cmdlets.

After creating the Shared Mailbox, open EAC in on-premises Exchange and Microsoft 365. Then go to recipients > shared and check the Shared Mailbox. The Shared Mailbox should be visible in both organizations. You can edit or view the details using the Edit icon.

To test the mail flow to Shared Mailbox, draft an email from the on-premises Exchange and Office 365 user accounts in Outlook and send them to the Shared Mailbox you created. Before sending the email, click the 'Request a Delivery Receipt' option.

If the mail flow is working fine, you will get a delivery receipt in the on-premises Exchange and Office 365 user's Outlook Inbox folder that the message has been delivered.

4. Test ActiveSync

To test ActiveSync, sign in to Outlook client on your Android or iOS smartphone and then send a test email from Office 365 or on-premises Exchange user's account to on-premises and external email servers, such as Gmail, and vice versa.

Also, send a test email from an on-premises Exchange or Office 365 user's account to your mobile device from Windows or Mac client.

5. Test Delegate Mailbox Access and Send-on-Behalf

To test Delegate Mailbox and Send-on-Behalf in Exchange hybrid configuration, you have the latest Azure AD Connect running and the latest CU installed. This will ensure there are no bugs or issues with cross-premises mailbox permissions.

You must enable the ACLable object synchronization via Exchange Management Shell by using Set-Mailbox and Add-MailboxFolderPermission PowerShell cmdlets for Send-on-Behalf and Delegate Access to work. ??

Once the permissions are assigned, verify Send on Behalf or Send As by drafting an email in Outlook from Office 365 user mailbox. Then, check if you can Send As or Send on Behalf of a group or user.

Similarly, check the delegate access to the assigned user's calendar from your Office 365 account. Try creating new events, meetings, or appointments in the user's calendar to verify that delegate access is working.

Finally, after performing these tests, move your mailboxes if you find everything is working fine.

To Wrap Up

Both planning and testing are equally essential when it comes to on-premises Exchange Server to Office 365 migration. To avoid scenarios where users can't connect to their mailboxes, access mail items, send/receive emails, etc., you should perform thorough post-migration checks before migrating the mailboxes to Office 365.

In this article, we shared Exchange hybrid test plan checklist that you can follow to ensure everything works fine and as intended and nothing is broken or requires a fix. Once verified, you can use Remote Move Migration , Cutover Migration , or a third-party EDB converter tool, such as Stellar Converter for EDB , to move your mailboxes from on-premises Exchange to Exchange online (Office 365). The EDB converter software helps in quick and easy mailbox migration with minimal manual efforts. It's a faster and reliable way to move mailboxes from on-premises Exchange databases to another live Exchange server or Office 365 tenant directly.?