Microsoft KB Archive/818040

= Message Queuing Messages Are Not Delivered When Sent Through an ISA Server Computer =

Article ID: 818040

Article Last Modified on 5/9/2003

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APPLIES TO


 * Microsoft Internet Security and Acceleration Server 2000 Standard Edition

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SYMPTOMS
When you send many SOAP-compliant Microsoft Message Queuing 3.0 Direct Messaging messages to a Microsoft Windows XP-based computer over HTTP, you may exceed the destination computer's connection limit, and therefore some messages may not be delivered.



CAUSE
This issue occurs when you send the Message Queuing messages through an Internet Security and Acceleration ( ISA) Server computer. To successfully use Message Queuing 3.0 with ISA Server 2000, you must install ISA Server 2000 Service Pack 1 (SP1).

This issue occurs because ISA Server has a cache for the connections that it opens to servers. Because these connections are idle Transmission Control Protocol (TCP) connections when they are in the cache (after their original request is completed), and because Web servers may have timeout settings configured for idle TCP connections, a server may close the TCP connection when ISA Server 2000 tries to use it again. If one of these connections is closed after ISA Server 2000 sends a request and while it waits to receive a reply, ISA Server 2000 must open a new connection and resend the whole request.

However, when a Message Queuing message with a body element is sent, ISA Server does not have the whole request. To prevent a situation where the message is lost because of a TCP connection timeout, ISA Server opens a new connection for this type of request. This may cause the connection cache to be exceeded (flooded) in a scenario where all requests have a body element.



RESOLUTION
To resolve this issue, install ISA Server 2000 SP1.

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



STATUS
Microsoft has confirmed that this is a problem in Microsoft Internet Security and Acceleration Server 2000.

Keywords: kbbug kbfix kbprb KB818040

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