Office 365 – Distribution List Migration Version 2.0 – Part 14

Enabling hybrid mail flow post group migration.

When migrating a distribution group to Office 365 administrators have the ability to enable hybrid mail flow. Enabling hybrid mail flow uses on premises Exchange to provision objects that allow relay through the Exchange organization to the migrated object in Office 365.

 

In general, I encourage the enablement of hybrid mail flow anytime your Exchange organization is acting as an on-premises relay for applications or you still have mailboxes in the on premises organization that need to send email to distribution lists. If you are specifically aware of what distribution lists are in use by applications, you can enable it specifically for just those distribution lists.

 

Originally enabling hybrid mail flow was an option that needed to be enabled at the time of migration. If the option was not utilized then provisioning of the objects was a manual process. Newer version of Distribution List Migration 2.0 now allow administrators to enable hybrid mail flow after the group has been successfully migrated. The new commandlet is enable-hybridMailFlowPostMigration.

 

Here is an example:

 

$onPremCred = get-credential

$cloudCred = get-credential

enable-hybridMailFlowPostMigration -groupSMTPAdress testGroup@contoso.com -globalCatalogServer gc.domain.com -activeDirectoryCredential $onPremCred -logFolderPath c:\temp -exchangeServer webmail.contoso.com -exchangeCredential $onPremCred -exchangeOnlineCredential $cloudCred -OU OU=MigrationTest,OU=DLConversion,DC=domain,DC=domain,DC=com

 

In this example credentials are stored in different variables. The commandlet is invoked specifying the group, domain controller, exchange server on premises, and the associated credentials. The OU specified in this command is where to create the routing contact and dynamic distribution group if the routing contact cannot be located. By default, the routing contact should be present and the dynamic distribution list will automatically be created in the same organizational unit.

 

When completed the dynamic distribution group required to satisfy hybrid mail flow is now available.