Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2


Data type Range Default value


0 | 1



Specifies whether the system can add sites to the coverage area of this domain controller.

Domain controllers cover, that is, provide services to, the site in which they reside and to other sites listed in the value of the entrySiteCoverage. In addition, when the value of AutoSiteCoverage is 1, the system can add sites that do not have domain controllers to this domain controller's coverage area.

Value Meaning


The system cannot add sites to the coverage area of this domain controller.


The system can add sites to the coverage area of this domain controller.

The sites added to the domain controller's coverage are stored in memory, and a new list is assembled each time the Net Logon service starts or when Netlogon is notified of the site object changes. While Net Logon runs, it updates this list at an interval specified by the value of the entry DnsRefreshInterval.

To determine this extended site coverage, the Net Logon service uses information from Active Directory. It applies the criteria listed below to determine which domain controller can provide the best service to a non-covered site. By default, all domain controllers are candidates for a non-covered site. However, if you use this entry to exclude domain controllers from the selection pool, the system might not be able to select the best domain controller for the site.

The criteria are applied in the order shown, and each subsequent criterion is applied only if the candidate domain controllers are equal on all previous criteria.

  • Connection cost: The connection to the domain controller is less costly than connections to other domain controllers in the domain.

  • Most domain controllers: The site in which the domain controller resides has more domain controllers than other sites.

  • Alphabetical order (tie breaker): The name of the site in which the domain controller resides is earlier in the alphabet than the site names of other domain controllers.

This entry does not exist in the registry by default. You can add it by using the registry editor Regedit.exe.


  • This entry is used only when it appears in the registry of a domain controller.


  • The list of additional sites computed for each domain controller is recorded in Netlogon.log when the value of the entryDBFlag entry is at least 0x20. To direct Net Logon to record the process it uses to compute site coverage, set the value of the entry DBFlag to 0x2800FFFF.

See Also