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If you use Internet Security and Acceleration (ISA) Server 2000 in either a Web publishing scenario or a Web proxy scenario, ISA Server may not immediately expire a response that contains the Cache-Control: s-maxage=0 header. This header is used to tell a proxy server not to use an entry after it is delivered to the requesting client unless it first revalidates the entry with the origin server. A value of 0 means that the cached response should expire immediately.
This problem occurs because ISA Server does not immediately expire the content. ISA Server waits for the current time to be greater than the request time in whole seconds. ISA Server incorrectly returns cached content for new requests that are made to the same resource within the same second without first revalidating the entry with the origin server.
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.
You must install ISA Server 2000 Service Pack 1 (SP1) before you install the following hotfix.For additional information about how to obtain the latest ISA Server service pack, click the following article number to view the article in the Microsoft Knowledge Base:
313139 How to Obtain the Latest Internet Security and Acceleration Server 2000 Service Pack
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.
Date Time Version Size File name -------------------------------------------------------------- 10-Jul-2003 18:42 3.0.1200.281 178,448 Mspadmin.exe 10-Jul-2003 18:41 3.0.1200.281 103,184 Msphlpr.dll 10-Jul-2003 18:41 3.0.1200.281 392,464 W3proxy.exe 10-Jul-2003 18:41 3.0.1200.281 299,280 Wspsrv.exe
Note 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.
For additional information about Cache-Control headers, see section 14.9 in the Hypertext Transfer Protocol -- HTTP/1.1 RFC 2616.