ADMT - Exchange Query

Question

Hi Gang,

We currently have our old source domain connected to 365 with an old redundant Exchange 2003 box. To be clear, we have no on-prem mailboxes, it only acts as an SMTP relay and used to establish email addresses for new users. How we now create and assign 365 licenses to users:

1. Create the user
2. Establish email addresses by creating the SMTP address
3. Force or wait for a DirSync
4. Login to 365 admin and assign a 365 license to generate the mailbox and so on.

We are going to dismantle our source old domain and are going to migrate to a new target domain. We do not want to deploy Exchange Servers on the new domain as we want to utilise 365's exchange platform (if this is possible). At this time, we have updated the new target domain with the Exchange schema but don't wish to deploy the Exchange servers.

My questions:

1. By default, ADMT does not migrate Exchange attributes, which exchange attributes must I script so that these attributes exist in the new domain when the users are migrated and sync this new domain to 365? The attributes I think are needed are EmailAddresses and ProxyAddresses -  not entirely sure if there is more?
2. What does the process change to? Since we have the Exchange schema but no Exchange servers on the new, can we manage exchange related attributes on 365 i.e. assigning email addresses and licenses for mailboxes existing?
3. Our source domain still has that Exchange 2003 box (all it serves for is to create email addresses and SMTP records) and acting as an SMTP relay. Excluding the SMTP relay role, can we get rid of this box and push the management of exchange attributes to 365? Remember, it is not hosting any on-prem mailboxes, it just serves as a way to establish email addresses and relay for applications.

Sorry if I've not made myself clear enough but your help is greatly required!

Thanks,

Daniel

Answer 1

Hi Daniel,

Do you need any further assistance?

Best Regards,

Erick

Answer 2

Hi Daniel,

Question 1: so when migrating users from source to target domain I only need to ensure that the ProxyAddress attribute is migrated?

If this is your first time to sync accounts (no accounts in cloud), you can just keep the ProxyAddress attribute. However, based on your situation, I think you need to make sure that all related Exchange attributes in the link I provided are moved. Since you synced accounts from old domain to Office 365, all related attributes had already been synced to cloud. Now, you move to a new domain and only have the ProxyAddress attribute. If other Exchange related attributes are empty or not the same one in the new domain, these related attributes may be overwritten when you sync accounts from the new domain to cloud. Therefore, I suggest you move all related Exchange attributes to the new domain before syncing accounts again. After that, you can use the SMTP match to connect accounts.

Question 2: I see, so we have no choice but to deploy a new Exchange server? I've found this link, <https://support.microsoft.com/en-gb/kb/2939261> is this an option for us? Ideally, we really don't fancy migrating our 2003 Exchange box onto the new domain as the new target domain has a forest and domain levels of 2012R2.

The answer is yes. I think it is a good option for you. You can use it to set up Exchange server to manage related attributes.

Best Regards,

Erick

Answer 3

Hi Erick,

Generally, we can use*SMTP match to connect Office 365 accounts between AD and Office 365 cloud. You need to move all related cloud Exchange attributes before doing SMTP match. Here is a reference:*

*DirSync: List of attributes that are synced by the Azure Active Directory Sync Tool*

Understood, so when migrating users from source to target domain I only need to ensure that the ProxyAddress attribute is migrated?

The answer is no. Since you sync accounts from AD to Office 365 cloud, you must manage these accounts in AD.

I see, so we have no choice but to deploy a new Exchange server? I've found this link, <https://support.microsoft.com/en-gb/kb/2939261> is this an option for us? Ideally, we really don't fancy migrating our 2003 Exchange box onto the new domain as the new target domain has a forest and domain levels of 2012R2.

Thanks,

Daniel

Answer 4

Hi Daniel,

Do you need any further assistance?

Best Regards,

Erick

Answer 5

Hi Daniel,

Question 1: By default, ADMT does not migrate Exchange attributes, which exchange attributes must I script so that these attributes exist in the new domain when the users are migrated and sync this new domain to 365? The attributes I think are needed are EmailAddresses and ProxyAddresses -  not entirely sure if there is more?

Generally, we can use SMTP match to connect Office 365 accounts between AD and Office 365 cloud. You need to move all related cloud Exchange attributes before doing SMTP match. Here is a reference:

DirSync: List of attributes that are synced by the Azure Active Directory Sync Tool

Question 2: What does the process change to? Since we have the Exchange schema but no Exchange servers on the new, can we manage exchange related attributes on 365 i.e. assigning email addresses and licenses for mailboxes existing?

The answer is no. Since you sync accounts from AD to Office 365 cloud, you must manage these accounts in AD.

Question 3: Our source domain still has that Exchange 2003 box (all it serves for is to create email addresses and SMTP records) and acting as an SMTP relay. Excluding the SMTP relay role, can we get rid of this box and push the management of exchange attributes to 365? Remember, it is not hosting any on-prem mailboxes, it just serves as a way to establish email addresses and relay for applications.

As I mentioned above, you need to manage all attributes of accounts in AD.

If anything is unclear, please feel free to let me know.

Best Regard,

Erick