Article ID: 922861
You configure a computer that is running Microsoft Windows XP with Service Pack 1 (SP1) in the following way:
ipconfig /setclassid * myuserclassIf you configure a class ID, the fallback IP configuration of the client computer cannot be used. Therefore, the IP addresses of the default gateway, of the DNS servers, and of the WINS servers are unavailable. Network connectivity may be lost.
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 this specific problem. 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:
http://support.microsoft.com/contactus/?ws=supportNote 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.
PrerequisitesTo apply this hotfix, you must have Windows XP Service Pack 1 (SP1) installed.
Restart requirementYou must restart the computer after you apply this hotfix.
Hotfix replacement informationThis hotfix does not replace any other hotfixes.
File informationThe 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.
Collapse this tableExpand this table
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
When this problem occurs, the ipconfig /all command displays information that resembles the following:
Additionally, registry entries are removed from the following registry subkey:
Windows IP Configuration Host Name . . . . . . . . . . . . : xp1 Primary Dns Suffix . . . . . . . : contoso.com Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : contoso.com Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : 3Com 3C920 Integrated Fast Ethernet Controller Physical Address. . . . . . . . . : 00-01-02-03-04-05 Dhcp Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Autoconfiguration IP Address. . . : 10.10.99.99 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DHCP Class ID . . . . . . . . . . : myclassid
These registry entries may include the DhcpDefaultGateway entry.
For more information about a similar problem in Windows XP with Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:
915357For more information about the terms that are used in this article, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/915357/ )Network connectivity may be lost when you use DHCP to configure IP settings on a Windows XP Service Pack 2-based computer
(http://support.microsoft.com/kb/824684/ )Description of the standard terminology that is used to describe Microsoft software updates