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Even though an invalid address exists, a gethostbyaddr call may return successfully with a pointer to the hostent structure from another thread. In a private subnet without any DNS or WINS settings and when the NetBIOS over TCP/IP option is turned on, when you call gethostbyaddr in multiple threads to resolve addresses in the subnet, the program should return error 11004 (WSANO_DATA) if the address is invalid.
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 version of this fix should have the following file attributes or later:
Date Time Version Size File name ------------------------------------------------- 04-Apr-02 11:57 5.1.2600.41 149,120 Netbt.sys
To work around this problem, use a critical section to synchronize the call to gethostbyaddr among threads.
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.