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<\/figure>\n<\/div>Cross-forest migration is a tedious, complex, and time-consuming task. It requires expertise and technical knowledge to perform the migration. In this post, we will be explaining the stepwise procedure of cross-forest migration from Exchange to Exchange, Exchange to Office 365, and Office 365 to Office 365.<\/p>
Process to Perform Exchange to Exchange Cross-Forest Migration<\/h2>
Exchange to Exchange cross-forest migration<\/strong> is the process of moving mailboxes from one Active Directory forest to another. This migration requires careful planning as it involves transferring the user mailboxes, permissions, and configurations while ensuring minimal disruption. Here’s the process to perform the Exchange to Exchange cross-forest migration.<\/p> Note:<\/em><\/strong> Here, we will be taking Domain A<\/strong> as the old<\/strong> domain and Domain B<\/strong> as the new<\/strong> domain.<\/em><\/p>\n<\/blockquote> Step 1: Set up the New Exchange Server on Target Domain<\/strong><\/p> First, you need to set up the new Exchange Server on the target domain. For this,<\/p> Step 2: Configure the Destination to Receive Emails for Domains Hosted in Domain A<\/strong><\/p> Next, you need to add the accepted domains and email address policies. Here’s how:<\/p> Step 3: Configure the New Exchange Server to Act as a Remote Domain Connector for Domain A<\/strong><\/p> For this, do the following:<\/p> Step 4: Configure the Old Exchange Server to Forward all Inbound and Outbound Emails to New Exchange Server<\/strong><\/p> You need to configure the Old Exchange Server (Domain A) to forward all inbound and outbound emails to new Exchange Server (Domain B). For this,<\/p> Step 5: Create New Mailbox Databases on the New Exchange Server<\/strong><\/p> Now, you need to create mailbox databases on the new Exchange Server. For this, use the following command on the target Exchange Server:<\/p> Then, run the following command to mount the database:<\/p> Step 6: Migrate the Mailboxes to New Exchange Server<\/strong><\/p> Here are the steps you need to follow to migrate mailboxes to the new Exchange Server:<\/p> Exchange to Office 365 migration<\/strong> is the process of moving mailboxes, contacts, calendars, and other data from an on-premises Exchange Server<\/strong> to Microsoft 365 (Office 365)<\/strong>. Before you start the migration process, here are some prerequisites that you need to fulfil:<\/p> 1. Assess and Plan<\/strong><\/p> Assess the existing Exchange environment in Forest A and design the target architecture<\/strong> in Forest B. Additionally, you need to validate:<\/p> 2. Prepare the New Forest (Forest B)<\/strong><\/p> Configure Office 365<\/strong> in Forest B, ensure that the Cumulative Updates (CU)<\/strong> are installed, and Exchange schema is extended in Forest B. Add accepted domains<\/strong> (from Forest A and Office 365) to Exchange in Forest B. Then, ensure that proper name resolution and trust<\/strong> exists between Forest A and Forest B (if you will be using staged or ADMT migration). Now, migrate user accounts, groups, and SIDs<\/strong> from Forest A to Forest B. For this, use ADMT (Active Directory Migration Tool<\/a>).<\/p> 3. Prepare Forest B for Hybrid Deployment<\/strong><\/p> Now, prepare the Forest B for hybrid deployment. For this,<\/p> 4. Establish Hybrid in Forest B<\/strong><\/p> After fulfilling the above prerequisites, you can use the methods given below to perform the Exchange to Office 365 cross forest migration.<\/p> Method 1: Use the Active Directory Migration Tool<\/strong><\/p> You can use the Active Directory Migration Tool<\/a> to perform cross-forest migration. This tool helps migrate objects and restructuring tasks in Active Directory Domain Service (AD DS) infrastructure. You can use the tool to migrate users and groups between AD DS domains in same forest or different forests.<\/p> To use this tool, you need to perform multiple manual steps, which may lead to errors causing extended downtime. This can significantly affect the business and impact users’ productivity.<\/p> Method 2: Use the PowerShell Cmdlets<\/strong><\/p> You can migrate mailboxes from one forest to another using the New-MoveRequest<\/strong><\/a> b dv<\/strong> and the New-MigrationBatch<\/strong> commands. To run these commands, the user must exist in the target Exchange forest and have a minimum set of required Active Directory attributes. However, before you start the migration process, you need to prepare the target and destination servers.<\/p> For detailed process, read: Prepare mailboxes for cross-forest move requests in Exchange Server<\/a>.<\/p> However, there are a few limitations of this method:<\/p> Office 365 to Office 365 migration<\/strong> requires careful planning to ensure data integrity, minimal downtime, and seamless user experience. So, you need to first prepare your target and destination Microsoft 365 accounts for migration. Here are some prerequisites you need to consider:<\/p> 1. Purchase and Assign Licenses<\/strong><\/p> You need to purchase Cross-Tenant User Data Migration licenses<\/strong> for each user to be migrated. The licenses must be assigned to either<\/strong> the source or the target mailbox. Migration will fail without valid licensing. You need to also define the scope of users via mail-enabled security groups<\/strong> in the source tenant<\/strong>.<\/p> 2. Prepare the Target Tenant<\/strong><\/p> Use the Microsoft Entra Admin Center<\/strong>. Register a multi-tenant application<\/strong> with redirect URI https:\/\/office.com<\/a>. Record the Application (Client) ID<\/strong> and create a Client Secret<\/strong>.<\/p> Next, add Mailbox.Migration<\/strong> application permission for Office 365 Exchange Online, remove default User.Read permission, and Grant Admin Consent<\/strong> for your tenant.<\/p> Then, use the Exchange Online PowerShell<\/strong> to create a new MigrationEndpoint<\/strong>. Now, create or modify organization relationship (Target Tenant).<\/p> 3. Prepare the Source Tenant<\/strong><\/p> 4. Prepare Target User Objects<\/strong><\/p> <\/a>Once the above prerequisites are fulfilled, you can start the migration. You can move the mailboxes from the target tenant using migration batches. You can create migration batches using the New-MigrationBatch<\/strong> PowerShell cmdlet, and specifying a source endpoint, a CSV file containing target tenant email addresses, and a target delivery domain. The email addresses in the CSV must reflect the target tenant’s domain. Migration batches can also be initiated through the Exchange Admin Center.<\/p> After the mailboxes are moved, it is essential to update the MailUser<\/strong> objects in both source and target environments with the correct targetAddress<\/strong>, matching the target delivery domain. Once all migrations are finalized, you can clean up by removing migration endpoints and organization relationships using Remove-MigrationEndpoint<\/strong> and Remove-OrganizationRelationship<\/strong> cmdlets.<\/p> To see the detailed process, read: Cross-tenant mailbox migration<\/strong><\/a><\/p> You can use Stellar Migrator for Exchange<\/strong><\/a> to perform cross-forest migration of mailboxes. This software is suitable for the following types of migration:<\/p> This software will directly access the mailboxes on the source server and migrate them to the target server with a different AD forest. To use the software, you need to form a connection between the target and destination server, map the mailboxes, and start the migration process.<\/p> To see the detailed steps, refer: How to use Stellar Migrator for Exchange<\/strong><\/a>.<\/strong><\/p> In case of new MS Exchange deployment with a new domain name, you need to migrate the mailboxes from the current server to the new server in a different forest. For this, you can use ADMT and PowerShell cmdlets. However, to migrate mailboxes without any hassle, you can use Stellar Migrator for Exchange. The software can easily form a secure connection between the source Exchange Server and the target server, even if these are a part of different Active Directory forests. It can be used for migration between local Exchange servers and Microsoft 365 tenants. This software can also migrate mailboxes from local Exchange Server to Microsoft 365 and vice-versa.<\/p>\n","protected":false},"excerpt":{"rendered":"\n
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New-AcceptedDomain -Name \"DomainA.com\" -DomainName domaina.com -DomainType Authoritative<\/strong><\/code><\/pre>\n
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New-SendConnector -Name \"To-DomainA\" -AddressSpaces \"domaina.com\" -SmartHosts \"<DomainA Mail Server>\" -SmartHostAuthMechanism None -UseExternalDNSServersEnabled $false -SourceTransportServers \"Exchange2019B\"<\/strong><\/code><\/pre>\n
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New-SendConnector -Name \"To-DomainB\" -AddressSpaces \"domainb.com\" -SmartHosts \"<Exchange2019B IP\/hostname>\" -SmartHostAuthMechanism None -UseExternalDNSServersEnabled $false -SourceTransportServers \"Exchange2013A\"<\/strong><\/code><\/pre>\n
New-MailboxDatabase -Name \"DB1\" -EdbFilePath \"D:\\ExchangeDatabases\\DB1\\DB1.edb\" -LogFolderPath \"D:\\ExchangeLogs\\DB1\"<\/strong><\/code><\/pre>Mount-Database DB1<\/strong><\/code><\/pre>\n
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Process to Perform Exchange to Office 365 Cross-Forest Migration<\/h2>
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Process to Perform Office 365 to Office 365 Cross-Forest Migration<\/h2>
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Alternate Method to Perform Cross-Forest Migration of Exchange and Office 365 Mailboxes<\/h2>
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<\/a>Conclusion<\/h2>