Background:

For the oracle errors like “ORA-12170: TNS:Connect timeout occurred”, “ORA-12535: TNS:operation timed out”, “ORA-12560: TNS:protocol adapter error”, “TNS-00505: Operation timed out” and like others related to oracle listener it is useful of tracing the listener activities to dig down further.

Workaround:

1. Connect to the listener control utility from the command line or shell.

   • LSNRCTL

2. Run the below command to enable the tracing for ADMIN mode.

   • set trc_level ADMIN

3. Check the listener tracing file location and name.

• • lsnrctl status
    

  • Note: Turning tracing for listener in USER or ADMIN mode create large trace file, so not to hamper services due to short storage issue only turn tracing on when it is needed. After the tracing completed delete the existing file from server.