Can I extend Active Directory schema to include Exchange Attributes?

Scenario

You want to ensure that when you send emails to Security or Distribution groups it works correctly. In this example, the ‘ReportToOriginator’ flag for the group needs to be set to ‘True’.

But, you have configured Signatures for Microsoft 365 (not On-Premises Exchange Server ), and you notice that certain Active Directory (AD) fields that relate to Exchange (example: ReportToOriginator) are not available. 

Reason

NOTE: The contents on this page have been sourced from How do I extend Active Directory schema to include Exchange Attributes?

Active Directory (AD) may not include Exchange attributes that require changes in the Microsoft 365 settings when a user is synced with Active Directory.

Resolution

To resolve this issue, you will need to add these attributes and the Active Directory Schema must be extended to include the Exchange attributes.

For example, the HiddenFromAddressListsEnabled setting in Microsoft 365 cannot be set from Active Directory unless the msExchHideFromAddressLists attribute is present. After extending the AD Schema, the msExchHideFromAddressLists setting will not sync unless the mailNickname attribute in AD is also set.

To extend the AD Schema in Active Directory

1. Run the Exchange 2016 setup files. You should see the disc image file open as a Drive: as shown below. 
   In this example, the required Drive is E:
   
   
   Image sourced from https://support.zixcorp.com/app/answers/detail/a_id/1411
   
   
2. Open Command Prompt (.cmd) and choose to Run as administrator.
   
   
3. Enter the following command:
   
   XX:\Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareSchema
   - Replace XX with the drive letter, where ExchangeServer2016 or ExchangeServer2013 file is run from.
   
   
4. If the schema has been successfully extended, a message similar to this will be displayed:
   
   
   Image sourced from https://support.zixcorp.com/app/answers/detail/a_id/1411
   
   
5. Open Microsoft Azure Active Directory Connect, click Tasks to display a list of all the available tasks.
   
   
6. From the Additional tasks list, select Refresh Directory Schema:
   
   
   
   
7. Click Next until the schema is refreshed.
   
   
8. Now, open Active Directory Users and Computers and double-click a user.
   
   
9. Select the Attribute Editor tab. Scroll down to verify the Exchange attributes.  
   
   CAUTION! If the Attribute Editor tab is not visible, you will need to enable the Advanced Features ( View > check Advanced features) in Active Directory Users and Computers.
10. In the Attribute Editor tab, you will now see the ‘ReportToOriginator’ attribute.
    Set this to True, then synchronize it to Microsoft 365.