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Q174051: DHCP Server Fails to Lease Addresses for New Scope

Article: Q174051
Product(s): Microsoft Windows NT
Version(s): WinNT:3.5,3.51,4.0
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server versions 3.5, 3.51, 4.0 
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SUMMARY
=======

It may be necessary to remove an existing scope from a Dynamic Host
Configuration Protocol (DHCP) server and replace it with a new scope. For
example, you may obtain a registered class of IP addresses for your network or
you may be changing the class of IP addresses to accommodate more hosts or
networks. This article discusses the recommended method of performing this task.

MORE INFORMATION
================

When you need to change your DHCP scope range, it may be necessary to leave the
server's original IP address bound to the network interface card (NIC) for
connectivity reasons until all clients have obtained an IP address from the new
scope. However, if you just create the new scope, you may notice that 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 and this
IP address is the primary address found in TCP/IP properties. The additional
addresses are found in the Advanced Properties of TCP/IP dialog box.

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.

  -or-

- 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: Q161571
  TITLE : Using DHCP "Superscopes" to Serve Multiple Logical Subnets

NOTE: If you cannot change the primary IP address of your NIC and you must use
the second option above, leave the original scope active and exclude all the
addresses within the scope.
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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search
Version           : WinNT:3.5,3.51,4.0
Issue type        : kbinfo

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