Merging two businesses and domains

Discussion in 'Windows Server' started by Gorge, Jun 15, 2010.

  1. Gorge

    Gorge Guest

    Hi Guys,

    I have a business that is merging with another business. Eventually everyone
    is going to be on a new domain, but for the time being I have to do
    something to bridge the gap. Both customers are running Windows 2003 with
    Exchange servers. They are buying a new domain for email, and I was going to
    link both domains using a trust over a vpn. I've never done this with two
    exchanges in an organization before.


    1) Can two different exchanges co exist in the domain together?
    2) Can all the users share email address across the two domains? IE:

    Customer A has

    Customer B has

    They want to create

    Thoughts on how this can be achieved would be welcomed.
    Gorge, Jun 15, 2010
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  2. Meinolf Weber [MVP-DS], Jun 15, 2010
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  3. Mail Domains have nothing to do with Windows AD Domians

    Two Exchanges cannot be in the same domain together unless they are part of
    the same Exchange Organization (which your are not)

    There is no such thing as sharing email addresses,...but the email address
    has nothing to do with the Windows AD Domains. The AD Domain could be
    "" and the email domain could be "". You can
    add multiple address to a user, but the Exchange has to be adjusted to
    accept email for the particular domain if the domain part of the address is
    different. But that does not make the mail come to the Exchange, it only
    means Exchange will accept it if it does arrive. Exchange can accept mail
    for multiple Mail Domains

    Creating a Trust will let the Domains interact (but only to a point).
    Meinolf's post covers that, no need for me to repeat what he said.
    Phillip Windell, Jun 15, 2010
  4. The best thing you can do here is to "do nothing".

    Leave the Exchanges alone
    Leave the mail domains alone
    Leave the email addresses alone

    Create the Trusts between the Domains so that permissions can be granted
    back & forth between the domains,...for the most part that is going to be
    nothing but file sharing,...has nothing to do with, and has no real benefit
    concerning email. This is also a temporary thing.

    Then build the New Forest/Domain
    Migrate your AD Objects (users and machines) to the New Forest/Domain with
    Let the other company do the same with their AD Objects.
    When completed start using the New Forest/Domain,...the old will cease to

    The New Exchange in the New Exchange Oganization within the New
    Forest/Domain can be configured to accept mail from any of the old mail
    domains plus the new mail domain if you are going to use a new one. The DNS
    Hosting Provider just needs to point the MX records for all the mail domain
    names to the same place after you configure Exchange to accept all of them.

    To save old mail export it to PST files while the old system is up,...import
    the PSTs into the new mail boxes on the new Exchange. The PSTs do not
    *have* to be imported,...they can be left as local PSTs and just open them
    with Outlook.

    There is no "Exchange migration", just stop using the old and start
    using the new.

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, Jun 15, 2010
  5. Gorge

    Gorge Guest

    No problem.

    I understand the difference between a mail domain and an ad domain.

    My issue is, both companies need to receive email from the same domain in
    about two weeks time. If a trust is established, that will not solve this
    issue correct? Unless I move all the mailboxes to the other Exchange domain,
    that's all I can think of. Either that, or leave the domains as is and
    create contacts on the original domain that forward the email to the company
    that is merging.

    Does that make sense?
    Gorge, Jun 15, 2010
  6. It would if the users alter their Outlook Clients to use the new server with
    the new domain. Their old mail can be moved into PSTs first so they are
    still availalbe in Outlook after it is pointed at the new Exchange. They
    cannot use two Exchange Servers at once.

    They might be prompted for credentials when Outlook opens (but unsure),
    least until everything is finshed.
    That would work and would be one way that they can use "both" at the same
    time for a while.

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, Jun 16, 2010
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