ORA-12541: TNS:no listener

ORA-12541: TNS:no listener
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Resolution:

Now you have to follow below mentioned steps to resolve the ORA-12541 issue.

STEP-1: First check your listener status.
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C:\>lsnrctl status

The above command will show the current status of your listener.

STEP-2: Start the listener, if listener is not running.
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C:\>lsnrctl start

This command will start all your listener services.

STEP-3: Stop the listener, if listener is running.
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C:\>lsnrctl stop

This command will stop all your listener services.

STEP-4: Now restart the listener.
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C:\>lsnrctl reload

This command will restart all your listener services.

Note: If you want to see all the available listener commands. Type lsnrtcl help on command prompt and you will get all available options.

C:\>lsnrctl help

LSNRCTL for 32-bit Windows: Version 11.2.0.2.0 – Production on 02-DEC-2016 20:25:14

Copyright (c) 1991, 2010, Oracle. All rights reserved.

The following operations are available
An asterisk (*) denotes a modifier or extended command:

start                           stop                status
services                     version           reload
save_config              trace               change_password
quit                            exit                  set*
show*

STEP-5: very important thing which you have to do.
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Open sqlnet.ora file and make the changes as suggested.

ora-12541-error

Change NTS to NONE

SQLNET.AUTHENTICATION_SERVICES = (NONE)

Now restart the listener services and your listener problem ORA-12541 will be resolved.