How to change the default authorative domain in Exchange 2010

Posted on 2012-09-06
Last Modified: 2012-10-02

Looking for some advice and help. I have an Exchange server which currently has 1 authorative domains, the default.
I've just added a new authorative domain not set as the default. Mail records adjusted and now if I send email to a user at either domain it is delivered.
So far so good.
The reason for the second domain is a company name change which hasn't taken place yet.When it does I want to reverse the default, so senders are identified by the new company name and replied to using that domain but everyone will still receive mail sent to the old domain, at least for a while.
And so tot he question:
How do I change the default from one to the other and automatically generate the new addresses for each account?
If I look at the Accepted Domains tab under Hub Transport of the Management Console there appears to be no way to 'set default' although the current domain is marked as True and the new domain as False.
I think I need to edit the Email Address Policy on that corresponding Tab and add the new authorative domain to the Policy which will add the new address to all users, is there an option here to set the default?
Any help would be appreciated, I can't step throught he process as i am not ready to change the domain email addresses until the date of the company name change, but I want to be prepared.

Question by:RossJaye
    LVL 10

    Expert Comment

    You're looking in exactly the right place.

    For your default domain, you simply right-click the domain you want to make default, and click "Make Default".

    To have users email sent out as your new company name, you edit the Default Email Address Policy, and right click the domain that you wish to make the default REPLY-TO address, and this will (assuming your AD doesn't override things) update all email addresses to have the default REPLY-TO address as the new domain.
    LVL 10

    Expert Comment

    p.s. You can add the additional email addresses using the Default Address Policy in advance of the change of name, and then simply make the switch when ready.

    The additional addresses in user's configurations won't be visible to the outside world (but will recieve mail!) until you change the default REPLY-TO address.

    Hope that helps.


    Author Comment


    Thanks for the replies, but it raises some questions and I like t know these things:

    If I edit the default Policy the new domain is not on the list of Email Addresses. Do I just click add and then add it in as a SMTP address and then right click the one I want and Set as Reply.

    If I do add in the new domain is appears on the list as unless I untick E-mail address local part when it appears as the old domain ie just What does this mean?
    LVL 10

    Accepted Solution

    Hi, sorry for the delay again.

    You need to add the domain into the "Accepted domains" section of exchange 2010 first.  Make it an Authoritative domain.
    Then it'll show up in your address policy.

    As for the %m, this is standard notation for "Use the Exchange Alias as the first part of the email address" as shown below.  You can configure all manner of custom email address formats using these:

    Custom SMTP e-mail address

     Given name (first name)
     Middle initial
     Surname (last name)
     Display name
     Exchange alias
     Uses the first x letters of the surname. For example, if x = 2, the first two letters of the surname are used.
     Uses the first x letters of the given name. For example, if x = 2, the first two letters of the given name are used.

    Author Closing Comment

    That's great thanks - All done

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