Oracle Windows TNS error: No Listener found

Oracle Database Tips by Donald BurlesonMay 9, 2015

Question: I'm getting a TNS "no listener" error on my Windows Oracle database when trying to connect:

LSNRCTL> status
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=<host name>)(PORT=1521)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
32-bit Windows Error: 61: Unknown error
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC0)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
32-bit Windows Error: 2: No such file or directory

How do I fix a "no listener" error?

Answer: The TNS no listener errors indicate that the Windows listener service is not accepting connections or the service is not running. The docs note the cause and action on the TNS No Listener errors, recommending to re-start the listener:

Cause - The connect request could not be completed because no application is listening on the address specified, or the application is unable to service the connect request in a sufficiently timely manner.

Action - Ensure that the supplied destination address matches one of the addresses used by the listener - compare the TNSNAMES.ORA entry with appropriate LISTENER.ORA file (or TNSNAV.ORA if the connection is to go by way of an Interchange.

Start the listener on the remote machine.

First, ensure that your listener service is running.

C:\Documents and Settings\ME>lsnrctl stat

Try to start the listener service using lsnrctl from DOS prompt.

set ORACLE_HOME= cd %ORACLE_HOME%/bin
lsnrctl start LISTENER

If the listener service is not running, re-start the listener service using the Windows task manager or use the DOS command line utility to re-start the Windows service with the "net start" command:

C:\Documents and Settings\ME>net start OracleOraDb10g_home1TNSListener

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