FIX: ISA Server Blocks Incoming Traffic Although a Valid Server Publishing Rule Exists

ISA Server may temporarily block incoming traffic that is destined for a protocol that has a valid Server Publishing rule defined. This blockage typically does not occur for more than a few minutes.

This problem occurs because some Winsock error messages are not handled correctly. When a connection enters a specified state, all traffic that is destined for the Server Publishing rule is blocked by ISA Server for a short time.

You must install ISA Server Service Pack 1 (SP1) before you install this hotfix. For additional information about how to obtain the latest ISA Server service pack, click the article number below to view the article in the Microsoft Knowledge Base: 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. To install the fix, run the self-extracting file. You do not have to restart the ISA Server computer. If the computer is part of an ISA Server array, you do not have to shut down the whole array. You can still install this fix on a one-by-one basis.

The English version of this fix has the file attributes (or later) 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. This fix also applies to the French, German, Spanish, and Japanese versions of ISA Server.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.