What is the purpose of listener in WebSphere MQ?

jms listener ibm-mq
Victor picture Victor · Aug 1, 2012 · Viewed 8.3k times · Source

When I go to my WebSphere MQ explorer, and connect to a remote queue manager and go to --> Advanced --> Listeners, I do not see any listeners defined. But I am able to create a remote JMS client, connect to this queue manager by using a channel connection and publish a message to a topic.

So what is the purpose of listeners? In my case, things are working fine without listeners.

Answer

T.Rob picture T.Rob · Aug 1, 2012

WebSphere MQ listeners are what accepts remote connections and start inbound channels. Modern queue managers will almost always have listeners defined but it is also possible to specify a default port for the QMgr to listen on without actually defining a listener. This is unusual, though. For older versions of MQ it was common to use inetd to start channels. This method doesn't use a listener.

So rest assured that something on your QMgr is listening for connections. Since you are not seeing it there are three likely possibilities:

  • The listener name starts with SYSTEM. and your Explorer view is set to filter SYSTEM objects.
  • The default port has been specified in the qm.ini file
  • You have a really old QMgr using inetd

By the way, go get a new version of WMQ Explorer. Since you have an Advanced --> Listeners you must have an old version. Download from SupportPac MS0T.

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