How to Solve Connection Error on Oracle Listener Control

This is an error that occurs from using Oracle’s lsrnctl start command to enable the Oracle database connection listener. Upon using that command, here’s the output of the error:

lsnrctl start

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 30-APR-2010 10:42:24

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.2.0.1.0 - Production

System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora

Log messages written to /u01/app/oracle/diag/tnslsnr/wrath/listener/alert/log.xml

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PACT)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))

TNS-12547: TNS:lost contact

 TNS-12560: TNS:protocol adapter error

  TNS-00517: Lost contact

   Linux Error: 104: Connection reset by peer

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=PACT)(PORT=1521)))

TNS-12541: TNS:no listener

 TNS-12560: TNS:protocol adapter error

  TNS-00511: No listener

   Linux Error: 111: Connection refused

This is probably caused by an incorrect configuration in the /etc/hosts file. So, make sure that inside this config file there is an entry for the loopback address like so:

127.0.0.1 PACT localhost

::1 PACT localhost

Note: The PACT value on the configuration file is due to the setup I use during my Oracle database installation. I use PACT as my hostname and have to put PACT as one of the entry in the /etc/hosts. But the point is, you have to have a localhost entry on the 127.0.0.1 and ::1. If done, save the file and start the lsnrctl service once again.

lsnrctl start

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 30-APR-2010 10:55:27

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.2.0.1.0 - Production

System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora

Log messages written to /u01/app/oracle/diag/tnslsnr/wrath/listener/alert/log.xml

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PACT)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))

STATUS of the LISTENER

------------------------

Alias                     LISTENER

Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production

Start Date                30-APR-2010 10:55:29

Uptime                    0 days 0 hr. 0 min. 0 sec

Trace Level               off

Security                  ON: Local OS Authentication

SNMP                      OFF

Listener Parameter File   /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora

Listener Log File         /u01/app/oracle/diag/tnslsnr/wrath/listener/alert/log.xml

Listening Endpoints Summary...

  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PACT)(PORT=1521)))

The listener supports no services

The command completed successfully