You can create a Job Monitor for the QINTER job in QINTER subsystem. Set it to monitor the “Job Status” metric. Select all of the job statuses that you think are important — Completed – Printer output available (and/or Printer output not available), Ended with error, Ending, End of job, Waiting for message,… whichever and however many you need.
Of course, if you have QINTER active and a previous QINTER has ended and left a joblog, your monitor will catch the one that was ended. That might be the case if QINTER was ended during nightly backups and restarted later. Further, your monitor would probably send an error report shortly after your backups started even though that’s the time that you want QINTER to be down.
Controlling the scheduling of your monitor will take some thought and some planning.
Also, if Management Central isn’t running, your monitor won’t be running. But that’s going to be true for any of your similar monitors.
You could write a trivial program that calls the Retrieve Subsystem Information (QWDRSBSD) API for format SBSI0100 which returns the “Subsystem status” value. You can submit that to some multi-threaded job queue such as QSYSNOMAX and have it loop forever. Call the API every 10 minutes or for whatever interval you need. You can have it send any message anywhere you want.
Of course, if QSYSWRK isn’t active, your monitor won’t run. Or if the *LIND is in an error state, there won’t be a useful network connection. Or if TCP/IP isn’t started or has a problem, you probably can’t send a message anywhere. Or if the telnet server isn’t started, it probably won’t make any difference if QINTER is active — your users won’t be able to use QINTER anyway (but your monitor won’t report any problem).
Also, if QINTER is active and the problem is network related, your monitor won’t be any help. Further, an external monitor won’t be able to check QINTER status — you actually would need a completely different kind of monitor.
In short, creating a QINTER monitor is easy.
Whether or not it’s useful is a very different question. It might cause more trouble than it solves.