DHCP Server Performance Degraded by Large Number of Scopes

ID: Q182047

The information in this article applies to:

Microsoft Windows NT Workstation version 4.0
Microsoft Windows NT Server version 4.0
Microsoft Windows NT Server version 4.0, Terminal Server Edition

SYMPTOMS

When a large number of scopes are configured on a Windows NT 4.0 DHCP server, performance degrades to where it cannot keep up with large client loads such as those experienced after a power failure, or at peak network startup times.

CAUSE

A list of scopes is maintained in the registry. When a DHCP DISCOVER or DHCP REQUEST is received, it must be matched against the configured scopes to see if the server is able to provide services to the client subnet. This process of searching through the scopes was not optimized for large numbers of scopes. Additionally, some database calls could experience suboptimal performance caused by nonoptimal database buffer initialization.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base:

Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

NOTE: This hotfix supersedes the fixes referred to in the following articles in the Microsoft Knowledge Base:

ARTICLE-ID: Q141496
TITLE : DHCP Client Comment Disappears When Obtaining IP Address

ARTICLE-ID: Q167708
TITLE : BootP Client Names Disappear in DHCP Manager

ARTICLE-ID: Q163055
TITLE : DHCP Client May Fail with WinNT 4.0 SP2 Multinetted DHCP Server

ARTICLE-ID: Q175035
TITLE : Diskless Workstations Cannot Find BOOTP Server with DHCP

STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

MORE INFORMATION

The updated file caches the entire scope list in memory, and uses a binary search to quickly determine if the server has a scope that is relevant to each client request. This update dramatically reduces the number of times that registry keys are opened and searched. It also provides more buffers for interaction with the database, which improves database throughput.

Additional query words: reduce

Keywords : NT4SP4Fix kbbug4.00 kbfix4.00.sp4 NTSrvWkst
Version : WinNT:4.0
Platform : winnt
Issue type : kbbug