We migrated a customer to a new domain a while back, but left their old domain controllers online for quite a while just to make sure no issues came up. After shutting them off, we did have name resolution issues which seem to have been resolved. What I can't get rid of, however, is the reference to the old WINS server on Windows XP DHCP clients. I can release/renew and get rid of it, but after a while, it seems to show back up.
What is causing this to show back up, despite it not being an option in the DHCP scope of the Windows 2008 R2 domain controller? Is there a way to clean all references to the old server from the network, or do I need to just manually disable WINS on each XP NIC?