This behaviour is by design. By default, target Primary SMTP addresses are set by the target organization recipient policies.
The DSA (Directory Synchronization Agent) can be configured to copy source Primary SMTP addresses to the target domain as is, without applying the target organization recipient policies, by adding one of the following registry values:
All proxy addresses are synchronized by the DSA by default and it is only the Primary SMTP address that is affected by setting these registry values.
Set this registry value if you would like to copy the Primary SMTP address only once, when the target object is mail- or mailbox-enabled.
After the initial sync has taken place, any changes to the Primary SMTP address of the source object will not be synchronized to the target object, even if a full re-sync is initiated.
Set this registry value if you would like to synchronize the Primary SMTP address every time the directory synchronization is run.
One-way synchronization
If the Primary SMTP address of the target object changes, while the DSA is running in the Delta synchronization mode, then the Primary SMTP address of the source object will not be re-applied to the target object until the source object changes in some way as well.
To work around this issue, edit any attribute of the source object to trigger the Delta sync or perform a Full Re-Sync. Often this may require the source primary SMTP being edited or added to the source object so Delta sync will replicate this change to the target object.
*This will only work if the 'mail' attribute and current Primary SMTP match on the Target object.
Two-way synchronization
Do not modify any source and target objects at the same time. Otherwise, the modified attributes may be overwritten.
This solution is compatible with Exchange Server 20xx.
This does not apply to the Directory Migration Agent for O365, only Directory Synchronization Agent (DSA) for On-prem to On-prem Migrations.
WARNING: Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986: Windows registry information for advanced users.
To add the registry values, complete the following steps:
1. Log on to the server where the DSA is installed.
2. Run the Registry Editor and open the following registry key:
For 32-bit platforms: HKEY_LOCAL_MACHINE\SOFTWARE\Aelita\Migration Tools\CurrentVersion\Components\MBRedirector
For 64-bit platforms: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Aelita\Migration Tools\CurrentVersion\Components\MBRedirector
3. Based on your migration project requirements, choose one of the registry values described above: CopyPrimarySmtp or SyncPrimarySmtp.
4. Add a new String Value with the chosen name.
5. Edit the newly created value and set it to 1.
6. Close the Registry Editor.
Additional Information:
Important: the Solution from above will only work if the Mail Attribute and the primary SMTP address have the same value.
For more information please see SOL24921.The Email Address Policies (EAP) are enforced in Exchange 20xx. Disable the EAP for all target mailboxes to which you wish to apply the CopyPrimarySmtp or SyncPrimarySmtp parameter. Otherwise, the target SMTP addresses will be restored as the primary SMTP addresses.
Using PowerShell:
Get-Mailbox -Id "Mailbox ID" | Set-Mailbox -EmailAddressPolicyEnabled:$false
Get-Mailbox -Server "Server Name" | Set-Mailbox -EmailAddressPolicyEnabled:$false
Using Exchange Management Console:
1. Open the Exchange Management Console.
2. Browse to 'Recipient Configuration|Mailbox'.
3. Right-click on the mailbox you want to modify and select 'Properties'.
4. Select the 'E-Mail Addresses' tab.
5. Uncheck the 'Automatic update e-mail addresses based on email address policy' checkbox.
6. Click OK.
