Are X.400 addresses needed in Exchange 2010?


  • Hello,

    My company is currently migrating mailboxes from an old Exchange 2003 environment to a new AD forest running Exchange 2010.  We are using a migration tool that copies Exchange mailboxes and settings over to the new environment and let's the 2 separate Exchange Organizations co-exist during the migration process by setting up secondary email addresses and utiltizing the target address AD field to forward emails from one Exchange organization to another.  We have running into an issue with our third party email archiving solution though because the archiving system sees the same email X.400 addresses for the same mailbox in both environments.  The vendor recommends that we remove all X.400 addresses on the Exchange 2010 organization to resolve the conflict.

    My question is how safe is this?  Does Exchange 2010 use X.400 adddresses or are they only for backward compatibility and are not needed anymore?  Will there be any issues if I do delete them?  Could it cause NDR's if a person replies to an email if the X.400 address no longer exists?

    If it is safe to remove them, what is the simpliest way to bulk remove X.400 address from thousands of Exchange mailboxes?

    Any idea?

    Monday, November 21, 2011 1:57 PM


All replies

  • Hi Steve,

    if using Exchange 2010 it is not necessary to use any X.400 address. Except you use an other application working on X.400 Addresses. But as you mentioned it is recommended by your application to remove the X.400 address. Inthis case I woiuld expect that you are able to delete those addresses. Exchange and Outlook are working without these addresses.

    If you want to change these adddressese by default you ar able to implement an E-Mail address policy.

    Start your Exchange Management Console - hub Transport Server - E-mail Address policy



    regards Thomas Paetzold visit my blog on: http://sus42.wordpress.com
    • Edited by Peddy1st Monday, November 21, 2011 7:44 PM
    Monday, November 21, 2011 7:40 PM
  • Hi,

    Pure Exchange 2007 and 2010 environments with no 2000/2003 servers do not necessarily require the X.400 address to function.

    But if you would keep old exchange server alive, I recommand you not to remove X.400 address.

    Still some more information for you:



    Best Regards!
    • Marked as answer by Steve March Tuesday, November 22, 2011 8:50 PM
    Tuesday, November 22, 2011 2:52 AM
  • Hi Steve,

    could I help you or have you got any further questions. It would be nice if you mark this topic accordingly, this may help others who have the same or a similar question.

    Thanks a lot in advance.

    regards Thomas Paetzold visit my blog on: http://sus42.wordpress.com
    Tuesday, November 22, 2011 8:18 PM
  • Thank you.  I began removing the X.400 email addresses from a few user accounts and have not experienced any problems so far.  I will start removing more to be safe but I think it is OK.  Thanks for all the replies.  I will investigate ADMODIFY as well to see if I can bulk remove them all. I assume there is some way to use Powershell as well.
    Tuesday, November 22, 2011 8:53 PM