How to migrate a domain controller to new server

Migrating a domain controller to a new server involves several steps to ensure a smooth transition with minimal downtime and no data loss. Here's a step-by-step guide to help you migrate a domain controller to a new server:

Preparation

  1. Plan the migration: Identify the reasons for the migration, assess the impact on your organization, and plan the migration timeline.
  2. Choose the new server: Select a new server with the same or better specifications than the old one. Ensure it has the necessary hardware and software requirements.
  3. Backup the old server: Backup the old domain controller's system state, including the SYSVOL share, to ensure data integrity.
  4. Prepare the new server: Install the necessary operating system, DNS, and DHCP services on the new server.

Step 1: Demote the old domain controller

  1. Open the Command Prompt: Run the Command Prompt as an administrator on the old domain controller.
  2. Demote the domain controller: Run the following command to demote the domain controller:
    dcpromo /uninstall /forceremoval

    This will remove the domain controller role from the old server.

Step 2: Promote the new domain controller

  1. Open the Command Prompt: Run the Command Prompt as an administrator on the new server.
  2. Promote the new domain controller: Run the following command to promote the new server as a domain controller:
    dcpromo /adv /domain /new /dc /install

    This will install the domain controller role on the new server and configure it as a domain controller.

Step 3: Transfer the FSMO roles

  1. Transfer the PDC Emulator role: Run the following command on the new domain controller to transfer the PDC Emulator role:

    netdom query fsmo

    This will display the current FSMO role holders. Then, run the following command to transfer the PDC Emulator role:

    netdom query fsmo /transfer /pdc

  2. Transfer the RID Master role: Run the following command on the new domain controller to transfer the RID Master role:

    netdom query fsmo

    This will display the current FSMO role holders. Then, run the following command to transfer the RID Master role:

    netdom query fsmo /transfer /rid

    Step 4: Update DNS and DHCP

  3. Update DNS: Update the DNS records to point to the new domain controller's IP address.

  4. Update DHCP: Update the DHCP server to point to the new domain controller's IP address.

Step 5: Verify the migration

  1. Verify domain controller status: Run the following command to verify the domain controller status:
    dcdiag /v

    This will display the domain controller's status and any errors.

  2. Verify DNS and DHCP: Verify that DNS and DHCP are functioning correctly and pointing to the new domain controller.

Step 6: Decommission the old domain controller

  1. Remove the old domain controller from the domain: Run the following command on the new domain controller to remove the old domain controller from the domain:
    netdom remove <old_domain_controller_name> /force
  2. Physically decommission the old domain controller: Physically decommission the old domain controller, ensuring it is no longer accessible or connected to the network.

Post-migration tasks

  1. Update group policy: Update group policy to reflect the new domain controller's IP address and other necessary changes.
  2. Verify application compatibility: Verify that all applications and services are compatible with the new domain controller.
  3. Monitor the new domain controller: Monitor the new domain controller's performance and functionality to ensure a smooth transition.

Remember to test the migration thoroughly before decommissioning the old domain controller to ensure a successful transition.