Select the product you need help with
- Internet Explorer
- Windows Phone
- More products
WINS Randomize1cList Feature Aids Load-Balancing Between DCs
Article ID: 231305 - View products that this article applies to.
This article was previously published under Q231305
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/256986/EN-US/ )Description of the Microsoft Windows Registry
You are experiencing logon and network validation problems on a network in which workstations and their associated domain controllers (DCs) reside on different subnets. This network is also configured to use WINS as the main vehicle for name resolution.
If domain controllers are monitored, one is found to be much more heavily loaded than the others. Monitoring the overloaded DC, and network traffic to and from it, reveals the following:
In Server Manager, you may see the following:
A new WINS server feature, Randomize1cList, is now available and can promote more even load balancing between DCs in these specific circumstances. For example, where the overloaded DC is the DC whose IP address is the first in the domainname<1C> list).
In a network that uses WINS for name resolution, a workstation's logon server is selected as follows:
If there are DCs on the workstation's subnet, one of these local DCs is usually selected as the workstation's logon server, as it receives the first broadcast SAM logon request earlier than remote DCs, and is therefore more likely to respond sooner than the remote DCs.
If there is no DC on the workstation's subnet, one of the DCs whose IP address appears in the domainname<1C> name query response is selected as the workstation's logon server. Normally, all the directed SAM logon requests are issued rapidly one after the other, and the first response is likely to be from the least busy DC. Over time, the usual result is each DC will become the logon server for a roughly equal numbers of workstations.
However, in some situations, it is possible for one of the remote DCs to be regularly selected as a workstation's logon server, causing it to become overloaded by subsequent volumes of validation traffic.
Windows NT 4.0 and Windows NT Server 4.0, Terminal Server EditionTo 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, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/152734/EN-US/ )How to Obtain the Latest Windows NT 4.0 Service Pack
Windows NT 3.51A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.
To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=supportNote In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
The English version of this fix should have the following file attributes or later:
Date Time Size File name Platform -------------------------------------------------- 06/08/98 06:23p 170,400 Wins.exe x86 06/08/98 06:24p 310,544 Wins.exe Alpha
How to Activate Randomize1cListWARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
After you apply the hotfix, you can activate Randomize1cList by modifying the registry as described below.
WARNING: In most networks, there should be no need to activate this feature. In some situations, it could actually have an adverse effect, depending on where the DCs in the domainname<1C> list are located. For example, changing the order of the list might cause workstations in London to select logon servers in Hong Kong. It is recommended that you activate Randomize1cList ONLY after performing a thorough network analysis, and confirming that doing so is appropriate to the observed symptoms along with your WINS and network configurations.
To activate the Randomize1cList feature after installing the fix:
Microsoft has confirmed that this is 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 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.
If there are no local DCs, one scenario that might lead to uneven laod balancing between DCs is network or router congestion. This can cause transmission delays between successive directed security account manager (SAM) logon requests. If such a transmission delay approaches the time required to receive a SAM logon request response from the first server in the DC IP address list, then it is likely that this DC will become the logon server for the bulk of the workstations in the domain.
An enhancement has been made to Wins.exe to provide a Randomize1CList feature to overcome this potential problem. With the Randomize1CList feature activated, the list of IP addresses in successive domainname<1C> name query responses is rotated a random amount before transmission to the workstation. This ensures a more even loading of DCs in problem scenarios, as described above.