DHCP Server With Deactivated Scope Sends a DHCPNAK to Clients

ID: Q228597

The information in this article applies to:

SYMPTOMS

When you start a Dynamic Host Configuration Protocol (DHCP) client, it tries to renew its lease on an existing IP address for its scope (Requesting state). Or in the case of the client never having an address, it will try to obtain a lease for an IP address for its scope (Initializing state). In the case where there are two or more DHCP servers on the network configured to service this segment, and a DHCP server has the scope for this segment disabled, the client may receive a negative acknowledgment (DHCPNAK) from the DHCP server with the disabled scope. If the client is running Windows NT Server or Workstation, the DHCPNAK would cause an event to be logged to the Windows NT System Event log. This will also increase network traffic and cause the client to needlessly fall back to an Initializing state.

Previous to Windows NT 4.0 Service Pack 4, this behavior was not present. This applies to Windows NT 4.0 Service Pack 5 as well.


RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp
The English version of this fix should have the following file attributes or later:

   Date      Time     Size    File name      Platform
   -------------------------------------------------------------
   4/15/99   8:00PM   125KB   Dhcpssvc.dll   i386
   4/15/99   7:59PM   199KB   Dhcpssvc.dll   Alpha

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:
Q154871 Determining If You Are Eligible for No-Charge Technical Support


STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0.


MORE INFORMATION

Administrators find that configuring two DHCP servers for the same scope then disabling one is an easy way to provide limited fault tolerance.

When the server with the active scope is unavailable, the DHCP server with the deactivated scope will assume the responsibilities for the DHCP clients of that scope.

For more information on how to configure DHCP, please see the following article in the Microsoft Knowledge Base:

Q139904 How to Configure Your DHCP Server Scope

Additional query words: 


Keywords          : 
Version           : winnt:4.0 SP4
Platform          : winnt 
Issue type        : kbbug

Last Reviewed: July 2, 1999