Question

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 1

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.