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Consider the following scenario:
Microsoft Windows XP Service Pack 2 or Microsoft Windows XP Tablet PC Edition 2005 is installed on your computer.
Note The features and components in Windows XP with Service Pack 2 are included in Windows XP Tablet PC Edition 2005.
A user class was defined on your computer by using the following command at a command prompt:
ipconfig /setclassid * Class_Name
In this command, Class_Name is a placeholder for the name of the user class.
You use a program that uses the DhcpRequestParams function to retrieve a configuration setting from a Dynamic Host Configuration Protocol (DHCP) server.
You set the ClassId attribute to NULL.
In this scenario, the DhcpRequestParams function returns ERROR_SUCCESS. However, the function returns no data to the program. This problem occurs even though the DHCP server returns all the required information.
This problem occurs when your computer is configured to use a user class.
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.
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, submit a request to 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 have Windows XP Service Pack 2 installed.
You must restart your computer after you apply this hotfix.
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 tool in Control Panel.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
When you perform a network trace, you can see the Windows XP client send a DHCP INFORM packet. In a DHCP INFORM packet, the Windows XP client sends the following information:
A request for the required DHCP options
The Windows XP client user class information
The reply from the DHCP server includes all the required information for the user class. However, the client information does not receive this information.
When this problem occurs, you may see a network trace that resembles the following.
Dhcp: Boot Request, MsgType = INFORM, TransactionID = 0xA7B5FCF4 Client IP address: 10.0.0.1 Your (client) IP address: 0.0.0.0 Next server IP address: 0.0.0.0 Relay agent IP address: 0.0.0.0 Client MAC address: 00:03:ff:49:96:7c Server host name not given Boot file name not given Magic cookie: (OK) Option 53: DHCP Message Type = DHCP Inform Option 77: User Class Information (5 bytes) Length: 5 UINT8(s) UserClassInfor: test1 Option 61: Client identifier Hardware type: Ethernet Client MAC address: 00:03:ff:49:96:7c Option 12: Host Name = "xp2" Option 60: Vendor class identifier = "MSFT 5.0" Option 55: Parameter Request List ... 222 = Private End OptionDhcp: Boot Reply, MsgType = ACK, TransactionID = 0xA7B5FCF4 Client IP address: 10.0.0.12 Your (client) IP address: 0.0.0.0 Next server IP address: 0.0.0.0 Relay agent IP address: 0.0.0.0 Client MAC address: 00:03:ff:49:96:7c Server host name not given Boot file name not given Magic cookie: (OK) Option 53: DHCP Message Type = DHCP ACK Option 54: Server Identifier = 10.0.0.254 Option 1: Subnet Mask = 255.255.255.0 Option 15: Domain Name = "fabrikam.com" Option 6: Domain Name Server = 10.0.0.253 Option 44: NetBIOS over TCP/IP Name Server = 10.0.0.253 Option 46: NetBIOS over TCP/IP Node Type = H-node Option 222: Private (2 bytes) Code: UNHANDLED DHCP OPTION CODE, 222(0xDE) Length: 2 UINT8(s) Value: DD End Option
For more information about how hotfix packages are named, click the following article number to view the article in the Microsoft Knowledge Base:
816915 New file naming schema for Microsoft Windows software update packages
For 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:
824684 Description of the standard terminology that is used to describe Microsoft software updates