1Z0-052 · Question #253
You manually create an additional listener process, L1, for databases PROD, PAYDB and FINDB. While starting up the listener process, you get the following error message: LSNRCTL> start l1 Starting…
The correct answer is D. change the port number to an unused port number and restart the listener process. The TNS-12542 error indicates port 8899 is already bound by another process, so listener L1 cannot start on that address.
Question
You manually create an additional listener process, L1, for databases PROD, PAYDB and FINDB. While starting up the listener process, you get the following error message:
LSNRCTL> start l1 Starting /u01/app/oracle/product/10.1.0/db_1/bin/tnslsnr: please wait... TNSLSNR for Linux: Version 10.1.0.2.0 - Production System parameter file is /u01/app/oracle/product/10.1.0/db_1/network/admin/listener.ora Log messages written to /u01/app/oracle/product/10.1.0/db_1/network/log/l1.log Error listening on: (ADDRESS=(PROTOCOL=TCP)(HOST=144.23.230.185)(port=8899)) TNS-12542:
TNS:address already in use TNS-12560: TNS:protocol adapter error TNS-00512: Address already in use Linux Error: 98: Address already in use Listener failed to start. See the error message(s) above... What action would you take to overcome this error without disrupting any existing database communications?
Options
- Astop and restart the listener process
- Bset the TNS_ADMIN environmental variable
- Cstop all running listener processes and restart the listener process
- Dchange the port number to an unused port number and restart the listener process
- Echange the IP address to host machine name in the LISTENER.ORA file and restart the listener
How the community answered
(34 responses)- B6% (2)
- C3% (1)
- D79% (27)
- E12% (4)
Why each option
The TNS-12542 error indicates port 8899 is already bound by another process, so listener L1 cannot start on that address.
Stopping and restarting L1 does not resolve the conflict because port 8899 is held by a different process, not L1 itself.
TNS_ADMIN controls where Oracle searches for network configuration files and has no effect on an OS-level port binding conflict.
Stopping all listeners would free port 8899 only if another Oracle listener owns it, but the underlying listener.ora still assigns port 8899 to L1, so the conflict recurs on the next start.
The error message explicitly states 'Address already in use' for port 8899, meaning another process has already bound to that port on the OS level. Changing the PORT value in listener.ora for L1 to an available port removes the conflict and allows the listener to bind successfully on restart.
The error is a port binding failure, not a hostname resolution issue; substituting a hostname for the IP address does not release port 8899 or fix the conflict.
Concept tested: Oracle listener port conflict resolution TNS-12542
Source: https://docs.oracle.com/cd/B19306_01/network.102/b14213/listener.htm
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