Were planning to remove a Domain controller out of the environment here. To this aim I have already done the following. 1. Built a new server, promoted to Domain Controller 2. Moved DNS 3. Moved WINS 4. Moved DHCP 5. Had the DHCP helpers added for new server on all routers/switches. Everything is working as expected and no issues. Unplug the OLD domain controller from the network and the network slows down. Plug it back in and all back to normal... Any ideas as to what may be causing it?More Info: The old server also used to be our file server, but all data was moved off this 10 months ago. All mapped drives were changed then in the login script. Any static mappings were manually deleted so the login script could recreate them.Dave

Hello, Thank you for your post here. From the description, you experience slow network after you unplug the domain controller. 1. To make us have a clear understand of your issue, could you please explain more about "slow network"? 2. Id like to know whether the you demote the domain controller before you unplug it. Please understand that if you want to remove a old domain controller permanently, you will need to demote the DC from the domain manually. The demotion will move the FSMO roles which to other DCs. 3. Could you please explain more about the domain structure? If there is multiple domains in the forest, please check how it works if you make the new DC as a GC. If you have any questions or concerns, please do not hesitate to let me know.

Hiwe have 1 domain.Currently have 2 DCs in the domain on old hardware.I now have 2 new DC's on new hardware.FSMO Roles have been transferred from the 1 DC to it's new replacement. (RID PDC Infrastructure Master)New DC has had DNS, WINS and DHCP Transferred. DHCP has been turned off on old server. GC has been taken of server and put on new server.DHCP, WINS and DNS working fine on new server. All scopes configured for new server. All Workstations have correct DNS and WINS server listed.I realise that we need to Demote server, but before we did this I wanted to know what would break when the server was removed, as after demotion the server will be removed from the domain.By Slowness on the network, This would be on File Browsing to the file server, A couple of network applications operating slowly, It's like things are looking for the server and struggling because it isn't there.Do you need anything else?Dave

Hello, Thanks for the update. Yes, it seems that those applications are redirected to the offline DC and it results in the delay. You may check how everything works if you demote the old DC from the domain. As you have the additional DC which you have moved FSMO roles to and enable GC on, it will be OK to demote the old DC. If you have any questions or concerns, please do not hesitate to let me know.