How to bring a server into child domain

Question

HI,

We have created parent-child domain controllers by adding child DC into forest of parent DC for same testing.

Parent domain: Alwayson.AG.Ad.Local
Child domain: ChildAd
Domain name on ChildDC: ChildAd.Alwayson.AG.Ad.Local

Now we want to bring a machine into child domain - IP address of child domain is added under DNS entry for this machine.

We have tried putting the machine in ChildAD and ChildAD.Alwayson.AG.Ad.Local domain with ChildAD\Administrator, ChildAD.AlwaysOnAG\Administrator and AlwaysOnAG\Administrator users. It keeps giving us different errors.

My ask is what is the proper way to do this ? I am new to Active directory stuff ? What should be mentioned under domain for that machine ? which user to use - admin of child dc or admin of Parent dc or parentdomain.child domain\admin ?

Do we need to establish some kind of trust between child and parent domains ?

Appreciate your insightful response and thank you for your time !!

Answer 1

Hello,

Thank you so much for posting here.

According to our description, yes, it is the proper way to do this. In my test, I brought a client computer into the child domain, and set IP address of child domain as preferred DNS server and joined this computer to child domain. My parent domain is book.com, and child domain is yt.book.com.

After that, we could log in to the child domain controller and check that this computer is showing in the Computer container in AD Users and Computers.

Then we could log in to this computer with yt\Administrator as shown below. According to our description, we could not log in to the computer with credentials, right? What are the error messages when trying with the credentials.?

There is no need to manually establish the trust between child and parent domains since it will be automatically established. To check the trust between child and parent domains, we could follow the steps:

1, Open AD Domains and Trusts, choose the child domain.

2, Right click child domain and choose "Properties"

3, Check the "Trusts" tab, and we could see that it is two-way transitive parent-child trust.

4, Click the parent domain and then Click the "Properties". Click "Validate" to validate the trust.

5, We could also verify the trust on the parent domain.

For any question, please feel free to contact us.

Best regards,
Hannah Xiong

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