Q. Common Listener Issues You Faced ?
It is not very common to find listener-related problems in Oracle, and most connectivity-related problems are generally associated with database server problems, such as shortage of memory.
Here are some common errors:
ORA-12500 TNS:listener failed to start a dedicated server process - This is generally associated with memory shortages or permission problems in UNIX.
ORA-3113 end-of-file on communication channel – This is generally a network failure
TNS-12547 TNS:lost contact – This can be corrected by increasing the connect_timeout_listener parameter.
TNS-12224 TNS:no listener – Clients will get this message if the listener process is not running.
ORA-12570 TNS:packet reader failure – This is a network problem.
ORA-12571 TNS:packet writer failure – This is a network problem
Note that in many cases, a failure of the listener will not be logged on the database server, but will instead be presented as a message on the client workstation. Hence, the vast majority of listener errors are reported by end-users.