The DhcpRequestParams function returns ERROR_SUCCESS and no data in Windows XP with Service Pack 2 or in Windows XP Tablet PC Edition 2005 (919250)

SYMPTOMS

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.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

To apply this hotfix, you must have Windows XP Service Pack 2 installed.

Restart requirement

You must restart your computer after you apply this hotfix.

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 tool in Control Panel.

File name	File version	File size	Date	Time	Platform
Dhcpcsvc.dll	5.1.2600.2951	112,128	13-Jul-2006	14:05	x86

MORE INFORMATION

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 Option

Dhcp: 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