In this one network I have, I am moving from a linux infrastructure to a Windows infrastructure. This has been a staged process.
Originally there was no Windows infrastructure. DNS, NIS, and DHCP all came from a pair of Linux servers.
When the Windows servers arrived, we configured an AD zone.
We then moved the DHCP server from Linux to the AD servers. At this point, the DHCP scope was set so that the DNS names and servers were still those on the Linux server.
Once the zone was complete, we changed the DHCP scope to use the AD names and servers instead.
Finally, we tried to decommission the linux servers.
However, some Windows clients are reverting to using the old DNS servers.
You can do an ipconfig /all and look at the network interface -- it will show you the AD server as the DHCP server, and the two Linux nodes as the DNS servers.
The thing is that they do this randomly -- some of them stick to the new servers, and some of them seem to flip back and forth between the new servers and the old servers.
Obviously I can't decommission the linux servers as it will strand several workstations.
I've dumped the scope and searched it for the IP addresses of the old DNS servers -- they are not there. I have tried deleting and recreating the DHCP scope, deleting and re-installing the DHCP service, and deleting everything and cleaning out the DHCP registry mess before reinstalling and recreating everything.
Clients are still reverting.
The scope in question has all-reservations in it, there is no dynamic pool. So recreating the scope isn't terribly painful (I have the netsh commands to recreate the scope and reservations tucked away).
Does anyone have any idea what I'm missing here.