How to Rename an Active Directory Domain

In this guide, I will show you how I changed my Active Directory domain name from hwtech.com to hwtechnet.com. Renaming an Active Directory domain is not always the best idea, especially in large and complex AD infrastructures. It is usually better to migrate users, computers, and servers to a new domain. However, for simple and small AD environments (test, pre-prod, or DMZ), you can easily rename your AD domain according to this guide.

Prerequisites

Before you start, ensure that:

• You have an up-to-date backup of your domain controllers.
• Replication works correctly in your domain, and there are no critical errors of domain controllers or DNS (How to check Active Directory health).
• There is no Exchange in your domain. You cannot rename an AD domain if Exchange is deployed in it (except for Exchange Server 2003).
• To rename a domain, you need Windows Server 2003 or newer (in this example, the functional level of the AD domain and forest is Windows Server 2016).

Steps to Rename the Domain

1. Create a DNS Zone for the New Domain

First, create a DNS zone for your new domain on your current domain controllers. To do this, open the dnsmgmt.msc snap-in, create a new primary Forward Lookup Zone with the name hwtechnet.com, and replicate it on all DNS servers in your old hwtech.com domain.

You can create a new DNS zone using PowerShell:

Add-DnsServerPrimaryZone -Name hwtechnet.com -ReplicationScope "Domain" –PassThru

Wait until the new DNS zone is replicated on all DCs.

2. Generate Domainlist.xml

Run the rendom /list command to generate a Domainlist.xml file with the current AD forest configuration.

rendom /list

Check the contents of the Domainlist.xml file:

Get-Content .\Domainlist.xml

3. Modify Domainlist.xml

Open the Domainlist.xml and replace all old domain names (hwtech.com) with the new ones (hwtechnet.com):

notepad .\Domainlist.xml

Save the file.

4. Show Forest Changes

Run the following command to show the changes to be made in the configuration:

rendom /showforest

5. Upload New Configuration

Upload the Domainlist.xml with the new configuration of AD partitions to the domain controller with the Domain Naming Master FSMO role:

rendom /upload

The FSMO role owners can be displayed as follows:

netdom query fsmo

6. Prepare for Renaming

The rendom /prepare command will check the availability of all DCs in the forest and if they are ready to be renamed. Ensure that the command does not return any errors:

rendom /prepare

7. Execute Domain Renaming

The command below will rename the domain. Note that domain controllers will be unavailable for some time and restarted automatically to apply new settings:

rendom /execute

8. Verify New Domain Name

Ensure that the new domain name is displayed in the domain properties. Note that the full computer name did not change. You must provide an account name in the format newdomain\username to log in to the DC.

9. Update GPO Bindings

Run the following command to update GPO bindings:

gpfixup /olddns:hwtech.com /newdns:hwtechnet.com

Update the NetBIOS domain name:

gpfixup /oldnb:HWTECH /newnb:HWTECHNET

10. Rename Domain Controllers

Add new names on each domain controller manually and make them primary ones:

netdom computername %COMPUTERNAME%.hwtech.com /add:%COMPUTERNAME%.hwtechnet.com
netdom computername %COMPUTERNAME%.hwtech.com /makeprimary:%COMPUTERNAME%.hwtechnet.com

Restart the DCs:

Shutdown –f –r –t 0

Only domain controllers need to be manually renamed. The rest of the computers and servers can be rebooted twice, and they will automatically switch to the new domain. This must be done after /execute and BEFORE executing the rendom /clean command.

11. Clean Up

Remove links to your old domain from AD:

rendom /clean

Unlock the domain configuration:

rendom /end

12. Verify Configuration

Open the ADUC (dsa.msc) console and make sure that it has connected to the new domain name and all OU structure, users, and computers remain in place.

Additional Steps

Note that you will have to do some extra steps to reconfigure some services (e.g., CA, Failover Clusters) to the new domain.

Credit: https://woshub.com/rename-active-directory-domain/ (opens in a new tab)