Set to the listener you want to trace
LSNRCTL> set cur LISTENER_TEST
-- Enable Trace;
LSNRCTL> set trc_level ADMIN
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_TEST)))
LISTENER_TEST parameter "trc_level" set to admin
The command completed successfully
LSNRCTL> set cur LISTENER_TEST
-- Enable Trace;
LSNRCTL> set trc_level ADMIN
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_TEST)))
LISTENER_TEST parameter "trc_level" set to admin
The command completed successfully