The DNS Server service on an RODC does not respond to DNS queries for several minutes if the link to some RWDCs breaks in Windows Server 2008

Consider the following scenario:

• You deploy a read-only domain controller (RODC) that is running Windows Server 2008 for a branch office. This branch office has only this domain controller.
• You install the Domain Name System (DNS) server role on the RODC.
• The RODC connects to some read/write domain controllers (RWDCs) in a remote central office through a wide area network (WAN) link.
• The WAN link breaks.

In this scenario, the DNS Server service on the RODC does not reply to DNS queries. This issue lasts for several minutes, and then is resolved automatically.

This issue occurs because one thread in the DNS Server service holds a critical section while it waits for a Lightweight Directory Access Protocol (LDAP) response from the remote RWDC. However, the thread releases the critical section after it receives the LDAP time-out error several minutes later because the WAN link is broken. Therefore, all threads that require the resource are blocked. These threads include a thread that responds to DNS queries.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must be running Windows Server 2008 or Windows Server 2008 Service Pack 2 (SP2) on your computer. Additionally, you must have the DNS server role installed on your computer.

For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: After apply this hotfix, you must create a registry key. To do this, follow these steps:

1. Click Start
   , type regedit in the Search programs and files box, and then press ENTER.
   If you are prompted for an administrator password, type the password. If you are prompted for confirmation, provide confirmation.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters
   
   
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type MaximumRodcRsoQueueLength, and then press ENTER.
5. Right-click MaximumRodcRsoQueueLength, and then click Modify.
6. In the Value data box, type 3, and then click OK.
7. Exit Registry Editor.

Restart requirement

You must restart the computer after you apply this hotfix.

Note If you stop the DNS Server service before you install this hotfix, you do not have to restart the computer.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Server 2008 file information notes

Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
  Collapse this tableExpand this table

  Version	Product	SR_Level	Service branch
  6.0.600 1 . 22xxx	Windows Server 2008	SP1	LDR
  6.0.600 2 . 22xxx	Windows Server 2008	SP2	LDR

• Service Pack 1 is integrated into the release version of Windows Server 2008. Therefore, RTM milestone files apply only to Windows Vista. RTM milestone files have a 6.0.0000.xxxxxx version number.
• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM files and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2008

For all supported x64-based versions of Windows Server 2008

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the branch office environment, visit the following Microsoft Web site:For more information about the DNS integer properties, visit the following Microsoft Web site: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information

Additional file information for Windows Server 2008

Additional files for all supported x86-based versions of Windows Server 2008

Additional files for all supported x64-based versions of Windows Server 2008