Change Netbios domain name to uppercase

This post can help you, if you’re trying to join your vRA deployment to an Active Directory domain, but you receive below error. No, it’s not linked to a wrong userid/password, in my case it was linked to the fact that my Active Directory Netbios domain name was in lower case.

Yes, I know what you’re thinking. By default, if you deploy a new Windows domain, the Netbios domain name is automatically set in uppercase. So if you follow the recommendations you wouldn’t have that problem. But in real-life it can happen that recommendations aren’t followed 🙂

I just want to share you my journey, because we actually changed the Netbios domain name from lower- to uppercase in a production environment. We changed it without impact on the environment. The domain contained SQL servers / SQL clusters / Citrix servers / AIX servers / NAS & storage devices.

In my post, I will explain you all the steps to perform. So keep on reading.

1. Check vRA appliance

After you received the error you first need to check the connecter.log (var/log/vmware/horizon/connector.log) on the appliance that you selected as “Sync Connector” when you’re binding towards your Active Directory.
There you will encounter the error that the “OU format is invalid”. When you search this error you will find this Vmware KB. Here they mention that the only option is to put your Netbios Domain name in uppercase.

If you don’t know what I mean with “Sync Connector”. Then it’s the appliance you choose when you’re adding your Directory as you can see in below printscreen.

2. Check Windows Active Directory domain

You can check your AD domain in 2 ways.

1. Powershell command (most acurate)

Get-ADObject -Searchbase “CN=Partitions,$((Get-ADRootDSE).configurationNamingContext)” -Filter {objectclass -eq ‘crossref’} -Properties nETBIOSName,dnsRoot|?{$_.nETBIOSName -ne $Null}|select nETBIOSName, dnsRoot

2. Active Directory Users and Computers snapin

You can simply Right Click on your domain and choose properties

There you will see in the Domain name if you’re netbios domain name is in upper- or lowercase. But be aware that once you have changed it to uppercase, it will remain in lower-case here. So the Powershell command will give you the most reliable output.

3. Change your domain to uppercase

I’ve found a great article about changing your domain name on RebelAdmin. But in my case, we only need to change it from lower- to uppercase. Which means that not all steps are needed, I’ll list the steps that are needed for our transfomation.

Making sure you have the necessary rights to change your domain config, start an administrator command prompt. Execute “rendom /list”. That will generate a DomainList.xml file.

The file is located in the same directory where you executed the command. Open “DomainList.xml” with Notepad and change the highlighted lowercase NetBiosName to uppercase. Save the file so your changes to uppercase are saved.

When your file is saved, you can now run “rendom /upload”. Check if it’s successful.

Next step is to run “rendom /prepare”. Always check if your command completes without errors.

And now we will execute the domain change. Execute “rendom /execute”. When this command is executed it will reboot your Domain Controllers after a few seconds.

After the reboot of the DC’s we have rebooted all the servers that are part of our domain.

Now you can run the same powershell command to check your Netbios Domain name. Now you should see it in uppercase.

If all checks out to be ok now there is still one command you will need to execute and that’s “rendom /end”. This will close of your domain change.

4. Join to AD domain

After executing all the above steps you should now be able to join your vRealize Automation environment to Active Directory. Hope this helps…

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