PROBLEM:

While starting the lister , getting below error.

# lsnrctl start LISTENER_TEST

LSNRCTL for Solaris: Version 12.1.0.2.0 – Production on 03-SEP-2018 09:34:26

Copyright (c) 1991, 2017, Oracle. All rights reserved.

TNS-01106: Listener using listener name LISTENER_DBACLASS has already been started

where ( listener.ora)

We are trying to start LISTENER_TEST, However, the error we are getting is LISTENER_DBACLASS already started. So how these listeners are related?

SOLUTION:

This error will come, when we are trying to start a listener with a port, which is being used by a different running listener. In simple words,
Two listeners cannot have same port.

Check the port being used by LISTENER_DBACLASS.

So the listener LISTENER_DBACLSS is using 1521 port. And the listener which we are trying start LISTENER_TEST also contains 1521 port.

So now change the port for LISTENER_TEST and start it.

We have changed from 1521 to 1523 in the listener.ora file

Start the listener.

It worked.