DNS data corruption occurs when the DNS records are transferred from a BIND DNS server to a Windows Server 2003 SP2-based DNS server

Consider the following scenario:

• There is a primary Domain Name System (DNS) zone on a Unix Berkeley Internet Name Domain (BIND) DNS server.
• There is a secondary DNS zone on a Windows Server 2003 Service Pack 2 (SP2)-based DNS server.
• The DNS records are transferred from the primary DNS zone on the BIND DNS server to the secondary DNS zone on Windows Server 2003 SP2-based DNS server.

In this scenario, the DNS records may be corrupted on the Windows Server 2003 SP2-based DNS server after the zone transfer. Therefore, when the Windows Server 2003 SP2-based DNS server receives a name resolution request, it will return the wrong IP addresses.

Note This problem occurs when the zone transfer format is configured as "many-answers" on the BIND DNS server.

The following are examples of the DNS records that are in the primary DNS zone on the BIND DNS server:

After the zone transfer, the DNS records in the secondary DNS zone on Windows Server 2003 SP2-based DNS server are changed unexpectedly:

When the zone transfer format is specified as "many-answers" on the Unix BIND DNS server, the DNS records are compressed on the BIND DNS server. During the zone transfer, the Windows Server 2003 SP2-based DNS server has to decompress the DNS records. However, if an error occurs in the decompression operation, the DNS records are corrupted.

Note To resolve this problem, apply the hotfix package on the affected Windows Server 2003 SP2-based DNS servers.

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 run a Windows Server 2003 SP2-based computer that has DNS server role installed. For more information about how to obtain a Windows Server 2003 service pack or a Windows XP Professional x64 Edition service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

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

Windows Server 2003 file information notes

• In addition to the files that are listed in these tables, this hotfix also installs an associated security catalog file (KBnumber.cat) that is signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2003

For all supported x64-based versions of Windows Server 2003

For all supported IA-64-based versions of Windows Server 2003

To work around this problem, change the zone transfer format from "many-answers" to "one-answer" on the BIND DNS server.

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

Zone transfer formats on the Unix BIND DNS servers can be set to two formats, such as "one-answer" and "many-answers." The transfer-format option is used on the master server to determine which format it sends.

The "one-answer" transfer format uses one DNS message per resource record transferred. The "many-answers" transfer format contains as many resource records as possible in a message. Although the "many-answers" transfer format is more efficient, it is only supported by new subordinate servers. These servers include BIND 9, BIND 8.x and BIND 4.9.5 onwards. The "many-answers" transfer format is also supported by recent Microsoft Windows name servers.

Note The default transfer format on the Unix BIND DNS server is "many-answers." The transfer-format option may be overridden for each server by using the server statement.

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