Quote Originally Posted by poling View Post
well, i spoke too fast. Yesterday after changing the port, all tnsping attempts were working fine while before several attempts per minute would fail. However, earlier today the problem is back again unfortunately.
Is the target host remote?

Set a job to ping host then check if ping fails at the same time you experience listener issues.

Set another job to tnsping host then check if ping and tnsping log errors correlate or not.