Prevent the Knowledge Consistency Checker from creating replication topology

This article describes how to disable the Knowledge Consistency Checker to prevent it from automatically creating replication topology.

Original KB number:   242780

Summary

Knowledge Consistency Checker (KCC) is a component that automatically generates and maintains the intra-site and inter-site replication topology. For more information about the role and function of KCC, see Active Directory Replication Concepts: KCC.

You can disable the KCC's ability to generate either the intra-site topology management or the inter-site topology management, or both.

More information

KCC runs at regular intervals to adjust the replication topology information. In some situations, you might want to tailor the replication topology by manually creating replication connections. In that case, you have to turn off the corresponding KCC functions to prevent KCC from overwriting your manual changes. The control settings for KCC are part of the Active Directory Domain Services (AD DS) site configuration. The settings are in the options attribute of the site's NTDS Settings object. The following table lists the relevant values for options.

Setting	Binary value	Decimal value	Description
NTDSSETTINGS_OPT_IS_AUTO_TOPOLOGY_DISABLED	0x00000001	1	Automatic topology generation is disabled.
NTDSSETTINGS_OPT_IS_INTER_SITE_AUTO_TOPOLOGY_DISABLED	0x00000010	16	Automatic inter-site topology generation is disabled.
NTDSSETTINGS_OPT_IS_INTER_SITE_AUTO_TOPOLOGY_DISABLED and NTDSSETTINGS_OPT_IS_AUTO_TOPOLOGY_DISABLED	0x00000011	17	All automatic topology generation is disabled.

For a full list of the flags and their bit values, see 6.1.1.2.2.1.1 NTDS Site Settings Object.

Note

When you disable the replication topology management function of KCC, you also disable the failure detection and rerouting function.

Important

If you disable one or more of the KCC functions, you have to find alternative methods to perform the following tasks:

• Monitor the network topology for changes that affect the topology information that's recorded in AD DS. Such changes include adding or removing sites or domain controllers. If such changes occur, update the AD DS topology information.
• Monitor the replication status of existing connections between domain controllers to detect replication failures. If a connection is not working, and a threshold is reached, build temporary connections to other replication partners (if available) to make sure that replication isn't blocked.

To disable or re-enable one or more of the KCC functions, follow these steps:

1. Open Active Directory Sites and Services (dssite.msc, also available on the Tools menu in Server Manager).

2. Expand Sites, and then expand the site that you want to modify.

3. In the right-hand pane, right-click NTDS Site Settings, and then select Properties.

4. Select the Attribute Editor tab. In the Attributes list, select options and then select Edit.

5. In the Value box, enter the new value (1, 16, or 17).

   Note

   The new value overwrites the previous value. To preserve a previous setting, adjust the value that you enter accordingly. If you want to remove the previous setting and re-enable KCC, select Clear.

6. Select OK, and then select Apply.

   The Attributes list displays the new value of options in both text and binary format.

To quickly check the KCC configuration from the command line, open a Command Prompt window, and then run the following command:

repadmin /showrepl <DomainControllerName> | find /i "site options"

Note

In this command, <DomainControllerName> represents name of the domain controller that you want to query.

For more information about how to use repadmin /showrepl, see Repadmin /showrepl.

Collecting data for Microsoft Support

If you need assistance from Microsoft Support, we recommend that you collect the information by following the steps that are mentioned in Gather information by using TSS for Active Directory replication issues.