ORA-12560: TNS protocol adapter error


Sometimes You can get “ORA-12560: TNS:protocol adapter error ” error.


Details of error are as follows.

ORA-12560: TNS:protocol adapter error
Cause: A generic protocol adapter error occurred.
Action: Check addresses used for proper protocol specification. Before reporting this error,
look at the error stack and check for lower level transport errors. For further details, turn on
tracing and reexecute the operation. Turn off tracing when the operation is complete.






To solve this error, run the relink all as follows.

$ORACLE_HOME/bin relink all


Then try to start again. It will work fine.


This error may be related with the Permission or ownership or group permission, so check them if they are ok or not.

Check permission.

[[email protected] ~]$ ll $ORACLE_HOME/bin/oracle
-rwsr-s--x. 1 oracle oinstall 239952653 Sep 11 20:36 /u01/app/oracle/product/12.1.2/dbhome_1/bin/oracle


Revoke the user execution permission from $ORACLE/bin/oracle as follows.

[[email protected] ~]$  chmod 6751 $ORACLE_HOME/bin/oracle

[[email protected] ~]$ ll $ORACLE_HOME/bin/oracle
-rwSr-s--x. 1 oracle oinstall 239952653 Sep 11 20:36 /u01/app/oracle/product/12.1.2/dbhome_1/bin/oracle


Or the second case of this error is as follows.

There is an invalid hostname in the TCP.INVITED_NODES list in the sqlnet.ora file.

Oracle no longer  allows  the listener to startup if an invalid hostname or ip address is specified in the invited_nodes list.  The listener will not start if any of the hosts or ip addresses are note resolvable.   The only solution to this issue is to ensure that all the hostnames and ip addresses in the invited nodes list are resolvable using ping or nslookup from the host where the listener is starting.

In some cases, the localhost might cause this behavior.


To solve this error, go to sqlnet.ora and check and fix the right INVITED_NODES IP as follows,

[[email protected] ~]$ cd $ORACLE_HOME/network/admin
[[email protected] admin]$ vi sqlnet.ora 




Or Check your Oracle Home and Oracle SID if they are set correctly or not.

Or Make sure that TNS_ADMIN is set correctly.
And also check your firewall settings.



Do you want to learn more details about RMAN, then read the following articles.



 2,265 views last month,  1 views today

About Mehmet Salih Deveci

I am Founder of SysDBASoft IT and IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience.I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource.I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks.I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients.If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress [email protected].-                                                                                                                                                                                                                                                 -Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  [email protected] a mail atabilirsiniz.

Leave a Reply

Your email address will not be published. Required fields are marked *