A Windows Server 2003-based DNS server does not forward a request to a target forwarder after you configure a conditional forwarder to resolve a DNS domain

Consider the following scenario:

• On a Windows Server 2003-based DNS server, you configure the conditional forwarder setting to resolve a DNS domain, such as partner.com.
• The target forwarder is a third-party DNS server.
• The network firewall rules let the DNS server connect only to the forwarder. They do not let the DNS server connect to DNS servers in its child domains or to other DNS servers in the partner.com domain.
• The DNS server receives a name resolution request for a host name, such as "record1.child.partner.com". Then, the DNS server successfully obtains a correct response from the forwarder.
• The DNS server receives a later name resolution query that also requires forwarding to the target forwarder, such as "record2.child.partner.com."

In this scenario, the Windows Server 2003-based DNS server connects directly to the DNS server in the child.partner.com domain instead of forwarding the request to the target forwarder. Because of the firewall rules, the name resolution request fails.

This issue occurs because the name server (NS) records from the query response to the child.partner.com domain are cached on the Windows Server 2003-based DNS server.

Therefore, later requests to the child domain use the cached information and are sent directly to the name servers that have just been learned.

Windows Server 2003 Service Pack 2

To resovle this issue, apply hotfix 978413. For more information about hotfix 978413, click the following article number to view the article in the Microsoft Knowledge Base:

Windows Server 2003 Service Pack 1

A hotfix is available to resolve this issue. After you install this hotfix, Windows Server 2003 DNS servers ignore the cached NS records and directly send name resolution requests to the target forwarder.

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 website: 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, the computer must be running Windows Server 2003 SP1.

Restart requirement

You have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other previously released hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003 SP1, x86-based versions

Windows Server 2003 SP1, x64-based versions

Windows Server 2003 SP1, Itanium-based versions

To work around the issue, modify the firewall to let the Windows Server 2003-based DNS Server access all DNS servers on the remote network.

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: