DHCP not working after demoting old DC
Posted on 2014-07-23
Today we demoted a legacy windows 2008 domain controller. It had previously been the PDC but we have since mad another 2008R2 server the PDC and have a 2012 server as a secondary DC. So I will call the servers as this -
Demoted server: Leg (2008 - DC/DHCP/DNS)
PDC (2008R2 - DC/DHCP/DNS)
SDC (2012 - DC/DNS)
After demoting the Leg server and removing the roles everything seemed fine. Until a user notified us later in the day that they could not log in. Tested and no machine can get DHCP. The Leg server had been powered down for a couple of weeks and all clients had been getting DHCP from the PDC. Why once we power it back on and demote it would all clients be unable to contact the PDC to obtain an IP address?
I have logged into the PDC and checked DNS. All the clients are registered there with the leases. But no machine can log on to the domain. They all get the message that no DC could be contacted.
I have logged in to the local machine and set a static IP address to see if they can connect this way but they are still unable to connect. But I am on a machine now that is still connected using a DHCP IP address.
Can anyone please give me some assistance in troubleshooting this issue? Please let me know what other info you need and I can supply it.
Thanks in advance.