Message Queuing Messages Are Not Delivered When Sent Through an ISA Server Computer (818040)

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.