Old Domain Controllers Showing as Authorized Servers

Question

I have 2 old domain controllers that no longer exist showing in the "Manage Authorized Servers" in "DHCP", when I try to unauthorize them I get an error that says "There is no such object on the server."

Answer 1

Try right click on ADSI Edit and click connect to. In connection settings, connection point, select or type a Distinguished Name or Naming Context. Enter CN=NetServices,CN=Services,CN=Configuration,DC=Your Domain,DC=com then click ok.

Expand the default naming context, highlight the path in the left pane, and you should see CN=DhcpRoot on the right.

Double click it, and then check for and edit the dhcpServers attribute to reflect the correct computers. The restart DHCP service.

--please don't forget to upvote and Accept as answer if the reply is helpful--

Answer 2

Yeah I added the current ones to the dhcpServers attribute and removed the old ones. The current ones are listed in CN=NetServices and 1 of the old ones is listed with them.

Answer 3

Awesome. Thank you so much!

Answer 4

You're welcome.

Answer 5

You can also use the Powershell comands remove-DhcpServerInDC and Add-DhcpServerInDC to add the DHCP server with the correct IP address and then remove the incorrect entry. e.g.

Add-DhcpServerInDC -DnsName "dhcpserver.contoso.com" -IPAddress 10.10.10.2

Remove-DhcpServerInDC -DnsName "dhcpserver.contoso.com" -IPAddress 10.10.10.99

This then meant that Get-DhcpServerInDC returned the correct DHCP server and the correct IP address.

https://learn.microsoft.com/en-us/powershell/module/dhcpserver/remove-dhcpserverindc?view=windowsserver2025-ps