Old DHCP servers still listed in Active Directory

With having completed a migration from SBS 2003 to seperate Domain Controllers and Exchange 2010 I noticed that when starting DHCP administrative tool from my workstation that when selecting the authorized DHCP server it still listed the old server along with the new server where DHCP was now running. Whilst this did not cause any real problems I wanted to clean it up and reduce confusion by only showing valid authorised DHCP server.

The command

Netsh DHCP show server

shows the authorised servers.

The command

Netsh DHCP delete server ServerFQDN ServerIP address

should remove the server from the list however I recieved the error:

• “There is no such object on the server”

To get around this I had to use the very handy (but potentially dangerous) tool ADSI Edit. To remove the old dhcp server reference you need to :

1. Start Adsiedit.msc.
2. Open the configuration Container.
3. Expand Services.
4. Expand Net Services.

In here I saw a reference to the server that was the old DHCP server and was now decomissioned and removed from the network. Therefore I selected the old server and deleted. A quick check again running

Netsh DHCP show server

showed the correct servers. Using the DHCP administrative tool it also showed the correct authorised server. A small point but keeping Active Directory clean is an important task.