My company has acquired new smaller company - Active Directory and Exchange consolidation ?

Senior IT System Engineer
Senior IT System Engineer used Ask the Experts™

My current company, let say (1000+ user base) has just acquired new smaller company of just 80-100 users last month.

They've got all on premise:
AD domain controllers - Single Forest domain called
File Servers ~ 12 TB on their office
Exchange server 2010 with email domain,, and [my current email domain is]
35+ Windows Server AD domain joined to
AD user account: [my current AD domain uses]

So how can I integrate them all into my Datacenter with the AD domain and converting all users to be ?

Where to start first so I can allow them to logon to my AD domain using & access email from my new company ?

I will create the separate thread for migrating:

Active Directory
Exchange Server
File Server

to my AD domain.
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AlexSenior Infrastructure Analyst
Your best bet would be to use something the Quest Active directory Migration toolkit, I've used it to migrate 7500 users and exchange mailboxes.
Might be for now you can consider creating mail contact for those users in your domain with whatever smtp address you want and set the external address as their current company SMTP address
EE Topic Advisor, Independant Technology Professional
I think I can answer this all at once:

I don't think it is worthwhile trying to get the domains working together if the end goal is to get rid of the other domain alltogether.

Since there are only a few users, you could write a script to export all the AD user accounts from Child and then import them to Parent.

Creating an email account can also be done in script, just make sure you arrange their name correctly when creating an email address. Also include a second email address for their old ChildCo domain. You'll then need to configure your Exchange server to accept mail for that domain. (As you said, how to do that last part could be a separate question).

For file access it should be easy if you just put the new users into existing security groups that you use for file access. Alternatively, you could export ChildCo's security groups, including members, with a script, but it would be best practice to avoid having legacy references when possible. As for files on ChildCo's file server, it would be up to your management, but the best thing to do would be get everything off their old server and integrate it in to your files server at ParentCo. This might be more work for people, but in the end in ensures everything integrate properly and also helps to get rid of any files that are not required.

My own personal note from having done this is once you are done and the old servers are ready to be shut off or repurposed, use a P2V tool to make virtual copies of all the ChildCo systems. That way if somebody discovers something was missed, you can spin them back up if needed.
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Quest for Domain migration is a good tool. I have used it with Zero errors! for 700 users.

However, as you said migration will be in a separate thread, and you just want to get them started with your parent company email addres, here are the things I would suggest -

1. Create a two way transitive trust between the AD domains.
2. Create linked mailboxes for the child company users.
3. As there are only 35 users in childco, I would suggest manual exporting/archiving their emails and importing to your parent company exchange server.
3. For point 2 above, add the child company public domains to your exchange accepted domains and Create the desired Email address policies if you want mails for and other domains of the child company to be received.

Let us know if this is what you are looking for?



The user is 85-100 mailboxes while the server is 35-45 mixed of Physical and VMs.
tomorrow, my network team will have the 100 MBps MPLS link connected to my data center, so after the firewall is opened, I can start to configure my AD to set the trust.

yes, the will be decommissioned.
Brian BEE Topic Advisor, Independant Technology Professional

Alex Green awarded himself the solution and majority of the points. Although the author abandoned the question, he did indicate that he would set up an AD trust and not use a tool like was suggested by Alex.
Brian BEE Topic Advisor, Independant Technology Professional

Senior IT System Engineer, since you just endorsed my answer, I assume you are still monitoring the responses. It would be better if you select the answers and assign the points yourself rather than have us do it.


Thanks for the response guys, I will go with the solution suggested and then create some subtopics based on this thread.

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