Cross Forest Migration mail flow between Exchange 2007 and 2010 RRS feed

  • Question

  • I'm planning to do a cross forest migration between Exchange 2007 SP2 and Exchange 2010 SP1. At the moment all email from the internet is directed to a spam filter appliance which relays the emails to the Exchange 2007 CAS/HUB. Outbound email is sent out straight from the CAS/HUB.

    For testing I have set up two forests. The source domain is 2k7.domain with Exchange 2007 SP2 and the target is 2k10.domain with Exchange 2010 SP1. At the moment they both have default recipient policies. I've been testing moving mailboxes with Prepare-MoveRequest.ps1 and ADMT 3.2, that seems fine so far.

    What I'm confused on in making sure that mail flows between the two forests during the migration of mailboxes. I would have thought I need to make sure that the recipient policies are the same in both Exchange organizations and that the accepted domains are the same? However what do I need to configure to keep mail flowing in from the internet to the recipients and between recipients to and from each forest?

    Do I need to set up a shared SMTP address space? Do I also need Internal Relay and send/receive connectors?

    Any help would be great.


    Friday, March 2, 2012 11:08 AM


All replies

  • If you are moving users from one forest to the other, and the user/email address will not exist on both sides at the same time then a shared SMTP namespace would work.  Simply create an SMTP connector on both sides with the local domain defined in the address space.  With this the Exchange server checks locally for the email address and if it does not find it defined locally, it will route the email to the other Exchange server which will in turn deliver it to a local mailbox.  Make sure both sides have this shared SMTP address space defined in the accepted domains.  The address space needs to be listed as an Internal Relay.

    To add loop protection, take a look at this - http://www.sysadminsblog.com/microsoft/shared-smtp-namespace-during-cross-forest-migration/.  Another good link for this migration - http://technet.microsoft.com/en-us/magazine/hh641445.aspx, and lastly http://blog.mimecast.com/2011/06/guest-post-migrating-between-email-servers-smtp-namespace-sharing-part-2/.


    • Proposed as answer by Evan LiuModerator Tuesday, March 6, 2012 9:55 AM
    • Marked as answer by Jawa126 Wednesday, March 7, 2012 12:56 PM
    Friday, March 2, 2012 10:48 PM
  • Thanks for the help, I've now got the shared SMTP address space working. I'm just running into the LegacyExchangeDN problem now when replying to previous emails after I have migrated a mailbox to the target domain!

    I'll take a look at the loop protection although my spam filter does first check that the recipient is valid before relaying the mail to the server. So I may be ok there.

    • Edited by Jawa126 Tuesday, March 6, 2012 10:08 AM
    Tuesday, March 6, 2012 10:02 AM
  • Just been reading that, very helpful.

    Does that mean that this is only a problem during co-existence until all mailboxes are migrated/moved? Doesn't it also mean that for mailboxes that have migrated they would need a x500 custom address of ALL users in the source domain that they may reply to?

    • Edited by Jawa126 Tuesday, March 6, 2012 1:43 PM
    Tuesday, March 6, 2012 12:58 PM
  • The value it adds is for the NK2 caching.  I would think that you need this for anyone kmoving and that it stays populated after the move.


    Tuesday, March 6, 2012 10:38 PM
  • Ok great, thanks for all the help.

    Wednesday, March 7, 2012 12:56 PM