This article was previously published under Q174051
This article has been archived. It is offered "as is" and will no longer be updated.
It may be necessary to remove an existing scope from a Dynamic HostConfiguration Protocol (DHCP) server and replace it with a new scope. Forexample, you may obtain a registered class of IP addresses for your networkor you may be changing the class of IP addresses to accommodate more hostsor networks. This article discusses the recommended method of performingthis task.
When you need to change your DHCP scope range, it may be necessary to leavethe server's original IP address bound to the network interface card (NIC)for connectivity reasons until all clients have obtained an IP address fromthe new scope. However, if you just create the new scope, you may noticethat the DHCP server does not assign leases from the newly created scope(s)after binding additional IP address(es) to the NIC.
This can happen because DHCP only binds to one IP address for each NIC andthis IP address is the primary address found in TCP/IP properties. Theadditional addresses are found in the Advanced Properties of TCP/IP dialogbox.
To make this transition, you will need to do one of the following:
Change the primary IP address on the NIC to an IP address that is a part of the same network as the new scope.
NOTE: This is the only option if you have Windows NT Server version 3.51 or Windows NT Server version 4.0 before Service Pack 2.
Configure the server to use a Superscope that includes the old scope(s) and the new scope(s).
For additional information, please see the following article in the Microsoft Knowledge Base:
ARTICLE-ID: 161571 TITLE : Using DHCP "Superscopes" to Serve Multiple Logical Subnets
NOTE: If you cannot change the primary IP address of your NIC and you mustuse the second option above, leave the original scope active and excludeall the addresses within the scope.