Procedure to host two AD domains on one Exchange server?

Posted on 2009-12-16
Last Modified: 2012-05-08

Can anyone direct me to (or just tell me) a procedure for hosting two AD domains on a single Exchange server?

I have a root and child domain with an exchange server in the child domain (child1).  Now I am adding another child domain (child2) and I want the users I configure in that domain to be hosted by my one Exchange server.  They are currently part of a separate AD forest so I created accounts for them in the child1 domain so they could use Exchange, but now that I am able to make them part of my central forest, I am not sure how to handle things.  I expect that I will have to delete their existing accounts from child1 and recreate them in child2 (that in itself is going to take some planning), but can they reside in child2 domain and still use the exchange server in child1 domain?

Thanks for your help.
Question by:cwickstrom
    LVL 8

    Expert Comment

    I'm in the process of doing the same thing, i found this article very helpful
    even though it says exchange 2000, it works on 03

    Author Comment

    Thanks for the response, but I already do this - I already host multiple smtp domains on my exchange server.

    What I want to do is to have multiple AD domains be able to use the same Exchange server instead of having to install separate Exchange servers for each domain in my tree.  There has to be a procedure for this but I can't find it.
    LVL 7

    Assisted Solution

    Make sure you have a backup of all servers including system state backups of each DC in your environment in case you need to roll back. You will need to prepare the new domain using the Exchange CD
    setup /domainprep

    "help adding domain to exchange 2003"

    "How to Run Exchange Server 2003 DomainPrep"

    "How to Verify That ForestPrep and DomainPrep Completed Successfully in Exchange 2000 Server or Exchange Server 2003"


    Author Comment

    CompanionCube - thanks for that last response.  It may be considered the answer to my original question.  Unfortunately it is not the answer to my original problem.  Here is what is happening:

    1. I verified that DomainPrep had been run on my child1 domain but I could not find proof that forestprep had been run on my forest (although I think I remember having done that).  Would Exchange work (as it has for the last 2.5 years) if either of those steps hadn't been properly performed?  If Forestprep was run, why can't I find proof of it using ADSI Edit?  What it hurt to rerun Forestprep at this point?

    2. I ran domainprep on my child2 domain and then tried to create a new RUS.  I keep getting the following error: "The RPC server is unavailable.  Facility Win32 ID no: c00706ba Exchange System Manager".  When I look up that error, I get pointed to AD replication problems or something along that line (so far I haven't pursued that avenue because it scares me).

    3. I reran forestprep and ran domainprep on my root domain thinking I could maybe do some testing from the root.  However, when I try to create an RUS for the root, I get "The specified group type is invalid. Facility: Win32 ID no: c0072141 Exchange System Manager".  When I look up that error I see information about rights and GC availability and that sort of thing.  Right now I am trying some of that, but it is quitting time, so results will be reported in the morning.

    If I don't just get randomly lucky, I'm not sure where to go next.

    Any ideas?

    LVL 7

    Accepted Solution

    Check this article...

    Error c00706ba when adding an Exchange RUS for a child domain

    "1. Add a static WINS entry for the domain controller in the child domain.
    2. Configure WINS replication between child and parent domains.
    3. Add the hostname (not FQDN) to the hosts file in %windir%\system32\drivers\etc\hosts on the Exchange Server where you are trying to add the RUS.
    4. On the network adapter properties of your Exchange server, add DNS and WINS servers for the child domain"

    Please ensure you have a good backup of your domain/forest before making changes, including running domainprep and forestprep or any other changes to the AD schema. If any doubts, please contact MS support.
    LVL 74

    Expert Comment

    by:Glen Knight
    What exactly are you trying to achieve?

    Do you have 2 domains that you are merging or are you trying to setup a new domain to host additional mail?

    Author Closing Comment

    CompanionCube's original answer gave me the plan, but I found this plan elsewhere as well.  The second answer resolved a key problem and was a solution no one else was able to provide.

    Author Comment


    Your second response was precisely what I needed to accomplish what you suggested in your first response.  I added the netbios name of the destination DC to the hosts file of the Exchange server and the RPC c00706ba error went away and I was able to create an RUS for the child2 domain.  For that reason I have assigned points and accepted the solution.

    In answer to demazter, I am adding a domain to my forest (sort of merging a domain from another forest into my forest except that I am pretty much creating it from scratch).

    Unfortunately, while I considered this question closed, I will be posting another question because I think I'm still missing a step.

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