The DNS Server service may start without a valid IP address in Windows Server 2008 R2 if you configure the computer to use a dynamic IP address

Applies to: Windows Server 2008 R2


Consider the following scenario:
  • You install the Domain Name System (DNS) Server service on a computer that is running Windows Server 2008 R2.
  • You configure the DNS server to use a dynamic IP address.
  • You restart the computer.
  • The DHCP Server is not available or the switch port which the DNS Server is attached to has portfast deactivated.
In this scenario, the DNS Server service may start without binding to a valid IPv4 address. This behavior causes the DNS server to be unable to respond to name resolution request over IPv4.


This issue occurs because of a timing issue between the DNS Server service and the DHCP client.

Upon start, by default, the DHCP client tries to verify whether the previously assigned lease is still valid. In the above described scenario however, it cannot reach the DHCP server, therefore it takes more time to keep the previously used IP Address.

If the DNS service starts while the DHCP client is still validating, it will not find a valid IPv4 address to bind to.

Also, The DNS Server service registers for IP address change notifications to make sure that the service is informed of IP address changes, for example if the DHCP client service decides to keep the previous IPv4 IP address. However, the DNS Server service does not receive the notification if the computer receives an IP address in a certain time period. This certain time period is between when the service starts and when the service begins to listen for the IP address change notification. Therefore, the DNS Server service does not start by using a valid IP address if the computer receives the IP address in this certain time period.


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.


To apply this hotfix, you must be running Windows Server 2008 R2. Additionally, you must have the DNS server role installed.

Registry information

To use the hotfix, you do not have to change the registry.

Restart requirement

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

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 R2 file information notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • 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 R2" section. MUM 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 x64-based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Cache.dnsNot Applicable3,19810-Jun-200920:31Not Applicable
Dns.exe6.1.7600.20713695,80814-May-201001:50x64 Applicable60910-Jun-200920:31Not Applicable


To work around this issue, configure the DNS server to use a static IP address. 


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

More Information

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

824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional file information

Additional file information for Windows Server 2008 R2

Additional files for all supported x64-based versions of Windows Server 2008 R2
File nameAmd64_149acb045fa56cb4aedc355d41836f0b_31bf3856ad364e35_6.1.7600.20713_none_44c40da2d99dbd56.manifest
File versionNot applicable
File size710
Date (UTC)14-May-2010
Time (UTC)21:46
PlatformNot applicable
File nameAmd64_microsoft-windows-dns-server-service_31bf3856ad364e35_6.1.7600.20713_none_aace287a092c40ac.manifest
File versionNot applicable
File size158,131
Date (UTC)14-May-2010
Time (UTC)04:10
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size1,671
Date (UTC)14-May-2010
Time (UTC)21:46
PlatformNot applicable