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Exchange 2010 Mailbox Migration to Another Domain RRS feed

  • Question

  • Hello, need some help in planning a migration from one domain to another. This is what I have and what I need to do:

    Current Scenario: We have 500 Exchange 2010 mailboxes and user accounts in our domain for Company B. We host their email right now so the Exchange server is on our domain and we have user accounts setup for each mailbox. All of these mailboxes are in 3 databases on the same Exchange server and no other mailboxes are on this server except for Company B. This server is a VM and has a 3 TB VHD. Company B has their own domain with each user having a user account in this domain for sign-on to their computers and etc. So, they have their Company B user account with which they use to log in to the computer then when they launch Outlook or use OWA/Activesync they use the credentials tied to their mailbox to authenticate. MX records point their mail here to our SPAM Filtering device. We have a point to point from us to them. 

    Project: I need to setup Company B with their own Exchange Organiztion in their own domain and move their current mailboxes to the new Exchange server. 

    What is the best way to tackle this? I basically have 2 user accounts in 2 separate domains that I need to merge and move the mailbox for each user to the new Exchange server in Company B's domain. This is 500 mailboxes and about a TB of data. Is there a way to migrate the current VM to their domain? Will I have to export a TB of data to 500 separate PST files? Will I have to create 500 new mailboxes on the new email server, PST each mailbox, attach each PST to each new mailbox over at Company B or is there a better way to go??

    Thank you.

    Tuesday, June 2, 2015 2:30 PM

Answers

  • I'll start with the easy ones - no, you can't move the server to their forest.  Their forest doesn't know your Exchange server, and vice versa.  You don't have to migrate the data to PSTs - you can create mailboxes in the new forest and move their mail directly across.  What you are doing is an inter-forest mail migration (you just aren't moving all the mailboxes you currently host).  The following TechNet blog gives the steps you can use if you don't want to export everything to PSTs:  http://blogs.technet.com/b/meamcs/archive/2011/10/25/exchange-2010-cross-forest-migration-step-by-step-guide-part-i.aspx

    I'll add that if you can complete this in a short time period (say, over a weekend), you won't have to worry much about a shared SMTP namespace.  This will save you some heartache in the end.  If you can't complete the tasks in quickly, you should consider setting up the "shared namespace" using the information outlined in my response to the following thread on the same topic:  https://social.technet.microsoft.com/Forums/en-US/0acd53d1-f45c-4076-8466-a60f22a0c708/exchange-2010-migrate-mailboxes-from-origin-forest-to-resource-forest


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Tuesday, June 2, 2015 8:43 PM
    Tuesday, June 2, 2015 6:03 PM
  • A trust relationship is required for a cross-forest migration unless you intend to export all the mailboxes to PSTs.  The Exchange 2010 toolset allows you to move mailboxes directly from one Exchange organization to another (again, if you have the required trusts configured).  And if you move the mailboxes fast enough, you won't need to worry about co-existence.

    Your limiting factor for speed may be the amount of data you have ...


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Tuesday, June 2, 2015 8:43 PM
    Tuesday, June 2, 2015 8:14 PM
  • That's how I'd handle it.  I'd migrate some test mailboxes so I could get an idea of the timeframe it would take, but otherwise, you should be good.

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Tuesday, June 2, 2015 8:29 PM
  • If you read the remainder of that section, it says the following (my emphasis added):

    If you have administrative credentials only for your forest, you can use the procedure Create a Two-Way, Forest Trust for One Side of the Trust to create your side of the trust. Then, have the administrator for the reciprocal forest create a one-way, outgoing forest trust from his or her forest.

    The trust needs to be two way on the target side, and one way on the source side.  Your forest is the source, the other is the target.


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Wednesday, June 3, 2015 2:16 PM
    Wednesday, June 3, 2015 11:56 AM
  • You will need to ensure that you have fully configured OA in the new system so it will support these connections.  You can do this before you move their mailboxes across.  You are also going to have to configure the new system so it replaces your system as the AutoDiscover target for this domain.  This will need to wait until you start moving the mailboxes, or their Outlook clients will attempt to use their system before it's ready for them.

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Wednesday, June 3, 2015 2:52 PM
    Wednesday, June 3, 2015 2:50 PM

All replies

  • I'll start with the easy ones - no, you can't move the server to their forest.  Their forest doesn't know your Exchange server, and vice versa.  You don't have to migrate the data to PSTs - you can create mailboxes in the new forest and move their mail directly across.  What you are doing is an inter-forest mail migration (you just aren't moving all the mailboxes you currently host).  The following TechNet blog gives the steps you can use if you don't want to export everything to PSTs:  http://blogs.technet.com/b/meamcs/archive/2011/10/25/exchange-2010-cross-forest-migration-step-by-step-guide-part-i.aspx

    I'll add that if you can complete this in a short time period (say, over a weekend), you won't have to worry much about a shared SMTP namespace.  This will save you some heartache in the end.  If you can't complete the tasks in quickly, you should consider setting up the "shared namespace" using the information outlined in my response to the following thread on the same topic:  https://social.technet.microsoft.com/Forums/en-US/0acd53d1-f45c-4076-8466-a60f22a0c708/exchange-2010-migrate-mailboxes-from-origin-forest-to-resource-forest


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Tuesday, June 2, 2015 8:43 PM
    Tuesday, June 2, 2015 6:03 PM
  • I'll start with the easy ones - no, you can't move the server to their forest.  Their forest doesn't know your Exchange server, and vice versa.  You don't have to migrate the data to PSTs - you can create mailboxes in the new forest and move their mail directly across.  What you are doing is an inter-forest mail migration (you just aren't moving all the mailboxes you currently host).  The following TechNet blog gives the steps you can use if you don't want to export everything to PSTs:  http://blogs.technet.com/b/meamcs/archive/2011/10/25/exchange-2010-cross-forest-migration-step-by-step-guide-part-i.aspx

    I'll add that if you can complete this in a short time period (say, over a weekend), you won't have to worry much about a shared SMTP namespace.  This will save you some heartache in the end.  If you can't complete the tasks in quickly, you should consider setting up the "shared namespace" using the information outlined in my response to the following thread on the same topic:  https://social.technet.microsoft.com/Forums/en-US/0acd53d1-f45c-4076-8466-a60f22a0c708/exchange-2010-migrate-mailboxes-from-origin-forest-to-resource-forest


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Ok,thanks. I was actually just reading over this article. First question, do I need to create a Trust Relationship with Company B's domain first? Also, on Part III of the article he states that you either have to export to PSTs or do the co-exestince scenario, are you saying I won't have to do either if  I can move all of the mailboxes like say over a weekend? 

    http://blogs.technet.com/b/meamcs/archive/2011/10/25/exchange-2010-cross-forest-migration-step-by-step-guide-part-iii.aspx

    Tuesday, June 2, 2015 7:59 PM
  • Also, is the instructions indicated here the same as these?

    http://portal.sivarajan.com/2010/06/gui-interface-for-cross-forest-mailbox.html

    Tuesday, June 2, 2015 8:12 PM
  • A trust relationship is required for a cross-forest migration unless you intend to export all the mailboxes to PSTs.  The Exchange 2010 toolset allows you to move mailboxes directly from one Exchange organization to another (again, if you have the required trusts configured).  And if you move the mailboxes fast enough, you won't need to worry about co-existence.

    Your limiting factor for speed may be the amount of data you have ...


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Tuesday, June 2, 2015 8:43 PM
    Tuesday, June 2, 2015 8:14 PM
  • Thank you Will. I have about 1 TB of data to move, maybe less sans whitespace. We do have a point to point to Company B so network wise we can connect to them so I guess my best bet is to do the following:

    1) Form the Trust Relationship with Company B

    2) Use the ADMT tool to perform the cross-forest migration with the user accounts.

    3) Convert merged User Accounts to Mail Enabled accounts.

    4) Prepare the accounts with the Prepare-moverequest script

    5) Move the mailboxes from source to target 

    Correct? 

    Tuesday, June 2, 2015 8:24 PM
  • That's how I'd handle it.  I'd migrate some test mailboxes so I could get an idea of the timeframe it would take, but otherwise, you should be good.

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Tuesday, June 2, 2015 8:29 PM
  • Ok, thanks. I still have to get the new Exchange servers setup at Company B, repoint MX and issue SSL Cert for Company B as well, they are a ".local" so  I will have to also setup Split DNS for the SSL Cert. 
    Tuesday, June 2, 2015 8:42 PM
  • A trust relationship is required for a cross-forest migration unless you intend to export all the mailboxes to PSTs.  The Exchange 2010 toolset allows you to move mailboxes directly from one Exchange organization to another (again, if you have the required trusts configured).  And if you move the mailboxes fast enough, you won't need to worry about co-existence.

    Your limiting factor for speed may be the amount of data you have ...


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Will, would I need to do a "Two-way Forest Trust for Both Sides"? 

    https://technet.microsoft.com/en-us/library/cc816590%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396 

    Tuesday, June 2, 2015 8:45 PM
  • If you read the remainder of that section, it says the following (my emphasis added):

    If you have administrative credentials only for your forest, you can use the procedure Create a Two-Way, Forest Trust for One Side of the Trust to create your side of the trust. Then, have the administrator for the reciprocal forest create a one-way, outgoing forest trust from his or her forest.

    The trust needs to be two way on the target side, and one way on the source side.  Your forest is the source, the other is the target.


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Wednesday, June 3, 2015 2:16 PM
    Wednesday, June 3, 2015 11:56 AM
  • Ok, thanks. I have administrative credentials for both sides. 
    Wednesday, June 3, 2015 2:16 PM
  • One more question please. Outlook clients. They are configured for the current exchange domain pointing over here with Outlook Anywhere, when they launch Outlook after the migration what is the best way to change their settings or will auto discover do this? 
    Wednesday, June 3, 2015 2:18 PM
  • You will need to ensure that you have fully configured OA in the new system so it will support these connections.  You can do this before you move their mailboxes across.  You are also going to have to configure the new system so it replaces your system as the AutoDiscover target for this domain.  This will need to wait until you start moving the mailboxes, or their Outlook clients will attempt to use their system before it's ready for them.

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    • Marked as answer by ÁNLEIFR Wednesday, June 3, 2015 2:52 PM
    Wednesday, June 3, 2015 2:50 PM