On Demand Migration for Hybrid Exchangecurrently supports migrating content from Microsoft Exchange 2010/2013/2016/2019.

In this topic:

• Enabling Application Impersonation Rights
• Accessing the Mail Server
• Specifying Administrator Credentials
• Upgrading Throttling Policies
• Setting Up Mail Routing

Enabling Application Impersonation Rights

To migrate data from Exchange 2010/2013/2016/2019 you must enable Application Impersonation for the migration administrator account. This allows the migration administrator to impersonate all users on all your client access servers.

To enable Application Impersonation rights, use role based access controls, and create a role group that has Application Impersonation rights.

• For Exchange 2010, see https://msdn.microsoft.com/en-us/library/bb204095(v=exchg.140).aspx.
• For Exchange 2013 and above, see https://msdn.microsoft.com/en-us/library/office/dn722376(v=exchg.150).aspx.

To create a role group for impersonation, use the PowerShell cmdlets from the articles above. The following is a step by step guide for creating the impersonation role and assigning a user to that role.

1. Log in to your Exchange server, or to a machine that has the Exchange Administration tools installed on it as an Exchange administrator.
2. Run Exchange Management Shell.
   
   
3. Run the cmdlet to create the management role group and assign the ApplicationImpersonation role to that group, and then assign the user you want to use as a migration administrator.

In the following example, we are using the user migAdmin@example.com.

New-RoleGroup -Name MigrationImpersonation -Roles ApplicationImpersonation -Members migAdmin@example.com

You can add multiple users using commas to separate each user.

Accessing the Mail Server

To migrate data from Exchange 2010/2013/2016/2019, make sure that Outlook Web Access (OWA) is accessible from the internet. On Demand Migration for Hybrid Exchange uses Exchange Web Services (EWS) to access your mail server from the internet. The OWA server name can be used for accessing your Exchange server with EWS. If you are not using HTTPS for OWA, you will need to enter the full URL for your EWS service which follows the format http://servername/EWS/Exchange.asmx.

You can find the URL for your EWS server using PowerShell. From the Exchange Management Shell, execute the following command:

Get-WebServicesVirtualDirectory | Select name, *url* | fl

The EWS server URL will be returned in the ExternalUrl value. To access the mailboxes slated for migration, the migrator needs to have an account with the ApplicationImpersonation role.

Specifying Administrator Credentials

When specifying the administrator credentials in the Migration settings screen, the Admin value is the account's UPN or Windows domain login (domain\samAccountName). Click https://technet.microsoft.com/en-us/library/cc756018(WS.10).aspx for more information about adding additional domains for UPNs.

It is recommended that you use auto-discovery to obtain the server URL. During a migration, this option uses the specified UPN and password to retrieve the server URL that hosts EWS for the given mailbox. You can also enter the server URL manually.

NOTE: Your Exchange 2010/2013/2016/2019 server must be configured to support auto-discovery before you can use it to obtain the server URL. Go to https://technet.microsoft.com/en-us/library/bb201695.aspx for information about Exchange 2010 Go to https://technet.microsoft.com/en-us/library/bb124251(v=exchg.150).aspx for information about Exchange 2013, 2016, and 2019.

If entering the server URL manually, enter the name of your Exchange 2010/2013/2016/2019 server in SSL format (e.g., exchange.example.com). If your server does not support SSL, enter the fully qualified URL for Exchange Web Services (e.g., http://exchange.example.com/EWS/Exchange.asmx).

Upgrading Throttling Policies

To minimize Exchange throttling impact to migration and to raise the overall migration throughput, we highly recommend to upgrade your throttling policies. Please raise the limits for the following throttling parameters to 'Unlimited':

Microsoft Exchange 2013/2016/2019

• EwsMaxConcurrency
• EwsMaxBurst
• EwsRechargeRate
• EwsCutoffBalance

Microsoft Exchange 2010

• EWSPercentTimeInMailboxRPC
• EWSPercentTimeInCAS
• EWSPercentTimeInAD

We recommend creating a custom throttling policy and assigning it to all the admin accounts used for your migration.

The upgrade can be done for the time of your migration only.

Setting Up Mail Routing

Before migrating or creating mailboxes, you must implement a mail routing strategy that will enable users to send and receive mail from both internal and external sources. There are different strategies to do this depending on how you want mail directed to and from the internet.

During the co-existence period of on-premises mail and hosted mail, you must decide which system will initially receive the email traffic for your organization. To make the best decision for your organization, please review the Microsoft documentation associated with your target email service:

• For Exchange 2010, see https://technet.microsoft.com/en-us/library/bb676395(v=exchg.141).aspx.
• For Exchange 2013, see https://technet.microsoft.com/en-us/library/aa998825(v=exchg.150).aspx.
• For Exchange 2016 or 2019, see https://technet.microsoft.com/en-us/library/aa998825(v=exchg.160).aspx.