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After you successfully connect to a domain controller by using an Extensible Authentication Protocol over LAN (EAPOL)/802.1x connection, you may not be able to receive Dynamic Host Configuration Protocol (DHCP) settings from the DHCP server.
This behavior can occur because the 802.1x driver processes TCP/IP packets asynchronously. However, the EAPOL-Key packets must be processed synchronously. If the EAPOL-Key packets are processed out of order, they are discarded. As a result, even if authentication with the domain controller succeeds, you may not be able to receive DHCP configuration settings.
To resolve this problem, obtain the latest service pack for Windows XP. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
322389 How to Obtain the Latest Windows XP Service Pack
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:
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.
The English-language version of this fix should have the following file attributes or later:
Date Time Version Size File name ---------------------------------------------------- 20-Dec-2001 18:13 5.1.2600.26 184,320 Wzcsvc.dll
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows XP Service Pack 1.
This Windows XP update modifies the 802.1x driver so that it processes each received packet before it reads the next one. This ensures that when client authentication succeeds, the EAPOL-Key packets are correctly introduced to the driver.