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Can not use second DC if DC Master not work

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  • Can not use second DC if DC Master not work

    Hi All,

    We have a server with DC. Now we buy the new server to replace the old one (too slow). We want to keep all user, rights and profiles of users so we use dcpromo with a Replica DC in an Existing AD Domain. Everything is OK if we run 2 servers. Unfortunately, the new server gets a lot of error if the old server is not working because we want to leave the old server

    For example: When we create new user in Active Directory Users and Computers in the new server is display:
    “Windows Cannot Validate the uniqueness of this proposed
    User name with a global catalog server because: The server
    Is not operational.
    windows will create this user account, but the user can
    log on only after the username is verified to be unique.
    For further assistance, contact your system administrator.”

    We don’t have any experience in this. Please help us to solver this problem.

    Thank you.

  • #2
    This error occurs because the 2nd DC is not a global catalog. Solve that by opening AD Sites & Services -> Sites -> Default 1st Site -> servers -> new DC -> NTDS Settings. Then select the properties of the NTDS settings and enablel the global catalog.

    other things to consider:
    - the new DC should run the DNS server service
    - all domain members should have _both_ DC's as DNS server in their TCP/IP properties.


    • #3
      Thank you for your support.

      We will do it now.



      • #4
        Before you demote the old server (via dcpromo) also remember to transfer the fsmo roles to the new dc. See for details