I have a Windows NT 4 network. My DHCP scope is 10.1.0.75 to 10.1.2.254 with a Class B mask. We are connected to the Internet through our ISP provider. There is another router with a PPP connection to another network. For the past six weeks, some clients have had difficulty logging on - no domain controller. IP config information on the computer shows an address received from a DHCP server at 10.0.1.1 with a Class C mask, and the IP address given to the client is 10.0.1.x with a Class C mask. Default gateway is 10.0.1.1. There are no other DHCP servers set up on my network.