MSMQ on Win2008 R2 will not receive messages from older clients

Question

I am struggling with a really strange problem. I have a Windows 2008 R2 server installed with a message queue installed. On another machine, running Windows 2003 is a service configured to send messages to the public queue on the 2008 server. However, messages never appear on the server.

I wrote a small console application that simply sends a "Hello World" message to the test queue on the 2008 machine. Running this application on XP or 2003 gives nothing. However, when I try to run the application on my Windows 7 machine, the message is delivered simply.

I had all kinds of security settings, disabled firewalls on all machines, etc. The event log is of no interest, and there are no exceptions to clients.

Running a packet sniffer (WireShark) on the server is shown only a little. When I try to send a message from XP or 2003, I see only the “Port Unreachable” ICMP error on port 3527 (which am I collecting for the MQPing package?). After that, silence. Wireshark shows a small packet flow when I try to execute my Win7 client (as expected - messages are received from Win7).

I turned on MSMQ End2End logging on the server, but only the records from messages sent from my Win7 computer appear in the log.

So, somehow it seems that messages are dropped quietly somewhere along the route from XP or 2003 to my 2008 server.

Does anyone have any clues as to what might cause this mysterious behavior?

Answer 1

A friend named John Broadwell ( http://blogs.msdn.com/johnbreakwell/default.aspx ) answered my tweets about this and pointed me to one of my own prompts, namely ICMP "Port Unreachable".

He referred to an article on a technology article that described how to re-enable the ping service running on port 3527. A simple registry file (and a reboot of MSMQ), and now my Win2008 server is happy to receive messages :-)