Can't deploy branch RODC

Question

I am trying to deploy a branch office RODC and am getting an error about extending the domain and forest schema. I know I have already done this in the past but I went ahead and tried from the main office DC. I get an error saying its already been extended when I try to use adprep.

History: There is a currently a single domain controller at the main branch. There used to be 3 domain controllers at the other branches and the admin had AD issues, so apparently he scaled back to the DC at the main office and gave the branches NAS storage. The branches are pointing across the VPN for DNS to the main branch DC.

I still see records in DNS for the old domain controllers, I am not sure how he went about demoting them, or if it was done properly at all. I was going to deploy some branch RODC servers and cache some credentials so they can continue to work off of a Windows file server and SQL server even when the VPN is down.

Any suggestions for tools to help me find the problem?

Answer 1

Did you go through the prereqs for an RODC available here:

http://technet.microsoft.com/en-us/library/cc731243%28WS.10%29.aspx

You must:

1. Run adprep /rodcprep in order to extend your schema. This is more than the typical domainprep and forestprpe
2. Be running your forest is running at 2003 level or higher
3. Have at least 1 writable DC running Windows Server 2008 or 2008 R2 deployed in the domain you're trying to add an RODC to.